Weber and Coulomb's MX-5

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coulomb
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Weber and Coulomb's MX-5

Post by coulomb » Sun, 01 Mar 2009, 07:22


Image

EVAlbum entry
Table of Contents

Battery Management System
Note: The devices referred to as "BMUs" here, are what we now call CMUs (Cell Management Units).
Veroboard prototype
Layout and BMS PCB prototype
Rev 28 layout and schematic
Digital BMU board and Rev 32 images
Squiggle joins on BMU boards with Rev 32 layout and Rev 32 schematic
BMU testing and block of 8 cells
Rev 45 BMU schematic and PCB with shunt diffamp circuit
When BMS go bad and a failsafe circuit that might prevent this in future
The six (possibly seven) changes to artwork around April/May 2011
The JTAG Tiny hack
DesignSpark usage tips
3D BMU images
Final BMU artwork sent; "semi x-ray" view
Accessing the celltopbmu respository for downloading or browsing PCB design files, BMU source code, and Driver Controls source code
Final BMU PCBs arrive
The 6 possible orientations of an optic fibre connector on a BMU
BMU parts arrive
Assembling production BMU boards
All BMUs complete
BMS "Disco" lights video
Novus fibre to USB interface (schematic, layout, photos)
Insulation monitoring units (IMUs) schematic and photo of manufactured PCBs; artwork

Bodywork
Alternative number plate holder
Soft top recoated
Engine lifter
Cleaning alloy wheels
Headlights investigations
Weighing the car
Removing the fuel tank
Engine lifting
Cutting monocoque bodies
Tilting the vehicle
Upgrading the brakes; update part two (new rotors and pads)
Replacing the auxiliary 12 V battery
August 2011 engineer visit
Reinforcing plates for front shock absorber towers
Air conditioning, idler, encoder, and vacuum pump bracket
Replacing the boot floor and correcting the speedometer reading
Speedometer cable ratio adjustment
Weight issues and corner scale results
Suspension spring calculations

Batteries
Thunder Sky cell tests
LiFePO4 charging (1)
Batteries arrive
Battery Racks
Rear battery rack lid cutout
Middle battery rack
Battery layout diagrams (1), (2), and (3) (detailed)
The High Tensions post.
Starting first contactor box
Battery boxes complete (or so we thought)
How did that get there?
Radiator and drive-shaft battery boxes assembled
Installing the front battery box
Installing the under-boot battery box
The front-mudguard battery boxes

Motor Controller and Cooling
The Control Techniques controller arrives
CT controller specs and more detail in the for sale post
Modifying for 240 V input (another thread, not us, we'd never do such a thing Image , but may be relevant)
Loo Tech Electricity Amplifier spoof (another thread)
Cooling gear arrives
Pump start voltage modification and final photos
The Tritium controller comes home
Pedal reading puzzle
Koolance Kooling Komponents Konnected
Coulomb's Neutral Wobble post (not directly related)
High voltage WaveSculptor arrives

Motor
Motor arrives
Motor performance curves
Motor mounting bracket
Cutting down the terminal box

Fitting and Adapting Components
Fitting motor and (not fitting) controller
Flywheel design
Adapter plate, adapter dimensions (text only) and KlaasDC's drawing
Driver Controls (DCUs)
Installing the potbox
Air conditioning pulley taper lock hub welding
Flywheel and clutch installation
Electric heater/demister and power steering and ceramic heater bought
Power steering pump motor controller, including circuit diagram
Completing the Driver Controls (DCU) wiring

Electrical wiring
Fuses arrive
Battery layout diagrams (1) and (2)
EV200 economiser noise; images here and here
Contactor boxes

Charger
Elcon charger arrives
Elcon charger RS232 experiments and partial CAN box circuit; using Driver Controls to send and receive CAN packets; using a CRO; 74C04 based converter (circuits here and here); how CAN IDs are constructed.
Code for talking to the charger and charger repair
Charger control and more
Charge algorithm
Industrial Fibre Optics connections

DC/DC
DC/DC selection
LED power supplies arrive

Power Steering
Power steering upgrade
Orientation
Power steering pump noise

Driving and General
Estimated power verses speed graph (another thread)
First drive with minor problems; video
At the 2011 AEVA Festival; see also 2011 AEVA EV Conference & Festival and video at the festival
First smoke (pre-charge resistor explosion)
First legal drive
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Goals

[ Edit: added Jan/2011; better late than never? ]

* At least the power of the 1.6 L petrol MX-5; preferably better than the 1.8 L model. If possible, better power to weight ratio than both.
* 100 kW mechanical (hopefully achieves the above, even with added weight)
* AC for regen; and a bit different to the usual DC conversion
* High voltage for lower current draw, thinner cables, and off-the-shelf induction motor (no rewind required)
* Lithium iron phosphate battery for longevity, range, reasonable performance
* Originally: industrial AC for cheap motor and reasonably priced controller
* Originally: reproducible, so we can make a series of these and sell them
* Open source where possible
* Rear wheel drive for the possibility of direct drive (retaining the gearbox was off again, on again for some time)

Specifications

* Converting a 1990 NA 1.6 MX-5, Australian model
* Motor: ABB 3GAA 131 008E 3-Phase AC 22 kW, 2 pole, long 132 frame, aluminium frame
* Controller: Tritium Wavesculptor200 165 kVA 450 V
* Battery: 218 x 40 Ah Sky Energy and CALB in angle iron cages
* System voltage: 360 V stage 1 (using 3.3 VPC for a round number near the typical resting voltage), 720 V in stage 2 (with 900 V controller)
* Drivetrain: Standard 5-speed manual gearbox and clutch; 3.636:1 diff (in place of stock 4.3:1).
* Chargers: 2 x TC Charger (Elcon) TCCH-417V-5.5A-CAN (sometimes known as TCCH-312-06) with CAN bus option.
* BMS: custom, using one MSP430G2452 on each cell; over/under volts, over temp, link over millivolts
* DC-DC: 2x Meanwell HLG-240H-15A power supplies in parallel across each half pack
* Expected top speed: 120 km/h (stage 1) and 160 km/h (stage 2)
* Expected range: ~ 160 km

Acronyms

* BMS - Battery Management System
* BMU - Battery Management Unit; one per cell; part of the BMS
* DCU - Driver Controls Unit; one per half-pack
* IFO - Industrial Fibre Optics, an inexpensive form of fibre optics based on plastic that can be used without specialised equipment

==================


Ok, we have a donor vehicle. We've both had the "sports car smile", and are looking forward to the EV grin. If this works out as planned, it might even be an EV hysterical laughter. If it pans, it might be an EV grimmace; we'll just have to wait and see.

Image

Know anyone who wants to buy a stock MX-5 1.6L engine? Runs really well. PM me for a test drive (Brisbane southside).

Image

We don't need no steenking exhaust pipe! Soon to be the "million dollar car". (The number plate really does end in AUD).

Hopefully more soon. Blackening the soft top is next.

Edit: had to work the "million dollar car" gag in there.

Edit: added table of contents, as per guidelines

Edit 11/2010: Broke up long list of contents into sections (thanks for the idea, Geerant!)
Last edited by weber on Fri, 23 Jun 2017, 08:43, edited 1 time in total.
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Post by acmotor » Sun, 01 Mar 2009, 07:37

And there I was thinking it was a bargain at AUD$10.60 !!

Yes 10^6 is a nice touch.
I hope it costs a little less to electrify !
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Post by coulomb » Sun, 01 Mar 2009, 08:43

Heh, the first picture is already out of date. We have installed an MX5-plus lightened aluminium number plate holder (mx5plus.com.au). I think we've save 200g already, plus about 1kg by removing the "baby teeth" (an MX-5 rite of passage).

Edit: I should point out that lightening is not the goal here, just a nice side effect. The point is to not damage the front bumper cover any further.

Here you can see that the number plate is held only by the bottom on an aluminium frame (just visible at the lower left of the plate). One of the marks made by the older frame is visible above the number plate (just above the second hole at the top), and that's after some work with high cut polish. As well as being heavy, the original plates damage the paintwork!

Image

Edit: Ok, I didn't have time to do a decent job on the numbers. So sue me Image
Last edited by coulomb on Tue, 03 Mar 2009, 17:14, edited 1 time in total.

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Post by coulomb » Sun, 01 Mar 2009, 22:36

Here are the hold downs; they weigh 750g each (including bolts that don't have to be replaced). There are two front and two rear, totalling 3.0kg.

Image
At left: front hold downs ("baby teeth"). Right: rear hold downs.

Note that I don't recommend removing the rear hold downs. They serve another purpose: they are the first thing that scrapes at the rear of the vehicle. Without the rear hold downs, the rear plastic bumper cover would rip off, and it would cosmetically be much worse than a little more wear on the hold down loop (you can see a little wear there in the photo).

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Post by EV2Go » Sun, 01 Mar 2009, 23:50

I guessing you never plan to accidently run out of power and need a tow on a tow truck???

You could save a few more grams on the number plates if you move to NSW, and driving on NSW roads I am sure you will lose even more with the bits that fall off driving on these crappy roads Image

Did you weigh it before you started to see what the actual different is post conversion? you can use factory specs but I dont know if they are always accurate.
Last edited by EV2Go on Sun, 01 Mar 2009, 12:52, edited 1 time in total.

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Post by coulomb » Mon, 02 Mar 2009, 06:17

EV2Go wrote: I guessing you never plan to accidentally run out of power and need a tow on a tow truck???
We did research this. It seems that as with any other car, you can tow it safely with a band attached near the front jack points. The manual actually says that the "towing hooks" are to be used only to haul the car out of a ditch, mud, or snow. For ordinary towing on two wheels, I don't really know where they lift it. The rear hooks are there, because without them scraping a driveway would rip the rear bumper cover.
Did you weigh it before you started to see what the actual different is post conversion? you can use factory specs but I dont know if they are always accurate.

We will do this. We've been told that you can use beams and about 8 bathroom scales. Next Thursday we'll start buying tools and two scales to try out the technique on perhaps one wheel.

Thursday is our designated EV day where we both are off work and try to be appointment free. We feel if we don't do this, interruptions will cause the project to be deferred indefinitely. We've seen this happen with other "weekend" projects.

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Post by coulomb » Mon, 02 Mar 2009, 06:32

Weber blacked the soft top today:
Image

You might not see it from the photo, but it looks pretty good now. The soft top was in good condition when we got it, but just faded. It seems to have been covered in "Armour-all", which most knowledgeable people say to avoid. It was even on the steering wheel, which is dangerous.

We also did some trivialities, like attending to a door handle that was sticking (now good), a window that wound up and down slowly (quicker now), etc.

My wife experimented with various environmentally friendly ways of polishing the car. She came up with an amazing number of them. We have a map of which parts were done with what technique, and will see which looks the best in a week's time.

We were pleased to find that some white marks that we assumed were paint worn through to the undercoat were in fact excess polish that hadn't been wiped down properly.

Looks like this will be a nice conversion, at least in appearance. We hope to make it good in performance as well.

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Post by coulomb » Fri, 06 Mar 2009, 07:34

We went tools shopping today; the most expensive item was the engine lifter. This is the 1,250kg from SuperCheap; about $365. We had no idea it would be so big. In fact, when we got the heavy package home, we realised that we had only one box of three. Sigh.
Image
That's a claw hammer it's holding (to gauge the size), and my garage door in the background. The length is over 1.8m.

Here is is in its "folded" configuration:
Image
Now it's almost 1.7m tall! For something that gets used so infrequently, maybe we should have hired one of these as needed. Oh well. I guess we can use it for battery trays, controllers, etc.

Here's Coulomb blissfully mounting the first castor... on the wrong side of the base! The instructions were terrible.
Image
You can also see the MX-5 on stands, and near the front wheel is the cheap (~$28) SCA hydraulic trolley jack that we used to get it on the stands. There was another brand a dollar cheaper, but it looked less solid, had a slightly higher minimum height, and a slightly lower maximum height.

Edit: added third picture and associated text.
Last edited by coulomb on Thu, 05 Mar 2009, 21:04, edited 1 time in total.

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Post by coulomb » Fri, 06 Mar 2009, 07:49

Part of a good EV conversion is making it look good. Our donor MX-5 has stock alloy wheels that are 20 years old; they looked a bit shabby. We cleaned them with steel wool; I recommend using a disposable glove, and using the stainless steel variety of steel wool. However, Weber believes that the plain steel wool works better, perhaps due to some chemical reaction where the alloy is actually etched. It's somewhat tedious cleaning all the little gaps that are hard to get to, but the result was quite good.

This photo doesn't do them justice. On the left is a wheel only cleaned with a high pressure "gerney"; on the right after cleaning with steel wool and spraying with a clear lacquer (Dulux Spraypak Quick Dry Clear).

Image

Weber painted the plastic inserts with aluminium paint. They have a "Mazda" logo in black in the middle; to mask this text, he filled it with olive oil using a toothpick. He also needed a toothpick to take out the oil later, since it mixed with paint particles. The result is quite an improvement; the plastic had worn down to white over almost half the visible area.

Edit: Weber prefers plain steel wool; lacquer detail.
Last edited by coulomb on Fri, 06 Mar 2009, 08:22, edited 1 time in total.

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Post by EV2Go » Fri, 06 Mar 2009, 20:40

Hey Coulomb, after I changed gears at 7500rpm and accidently selected angel gear at the drags and got back on the loud peddle (3 broken rockers), I needed the assistance of a tow truck to get my 180sx home. They used the tow hook at the rear to tie it down on the tow truck, because late model Japanese cars typically have IRS so there is no diff housing to tie down to.

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Post by coulomb » Sat, 07 Mar 2009, 03:59

EV2Go wrote: Hey Coulomb, after I changed gears at 7500rpm and accidently selected angel gear at the drags and got back on the loud peddle (3 broken rockers), I needed the assistance of a tow truck to get my 180sx home.
Image Sounds expensive! Sorry to hear that.
They used the tow hook at the rear to tie it down on the tow truck, because late model Japanese cars typically have IRS so there is no diff housing to tie down to.

Ok, they used what was available, but I don't think you would have been stranded if the rear toe hook wasn't there.

Also, we are keeping the rear tie downs, even if it is mainly for reasons other than towing.

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Post by Richo » Sat, 07 Mar 2009, 05:07

That's one big crane.
If you were in WA I would have gone halvsies with ya Image
btw I like you table of contents!
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Post by coulomb » Wed, 11 Mar 2009, 06:03

Richo wrote:btw I like you table of contents!

Just following the rules.

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Post by coulomb » Wed, 11 Mar 2009, 06:19

Weber decided that the more he drove the MX-5, the more convinced he was that he wanted power steering. So if we want it, a prospective customer is likely t want it. It so happens that some models of early MX-5 came without power steering, and others (especially the Japanese imports branded Eunos Readster instead of Mazda MX-5) come with. The two are basically interchangeable, as you can see with the two steering racks below:
Image
At top is the manual steering rack, and below is the power assisted version. Of course, the power version requires more parts not shown.

There is an idler wheel in the manual steering models, which can be replaced with the steering pump, though a different sized belt is required. A complete "kit" (well, a jumble of parts) is available from mx5plus.

I guess it was a fairly standard install, but it sure taxed us all the way. Without the proper tool, it took a lot of "drifting" (whacking with a hammer) to separate the steering rod from the steering nuckle. We found that supporting the steering knuckle on a hydraulic jack helped.

Edit: was "supporting the steering rod".

Some of the bolts were hell on earth to get to to undo and to tighten. Things will be so much simpler with the infernal combustion engine gone.

It was finally ready by about midnight Sunday, and only one bolt and one belt left over! Image   There always seem to be sme leftovers. (They weren't forgotten, they were not needed). A test drive confirmed that it works very nicely. After the test, we decided to chase up a slight clunk; it was the locking nut on the steering wheel connecting rod. Image
Last edited by coulomb on Tue, 10 Mar 2009, 20:35, edited 1 time in total.

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Post by coulomb » Wed, 11 Mar 2009, 06:40

We also investigated the possibility of making the pop-up headlights pop up less far. We have seem MX-5s where the pop-up lights are replaced with static low profile headlights. However, we feel it would look better to still be pop-up yet only pop up about halfway (110mm), using two 90mm lights (main and high beam). These are available commercially, but only at extortionate prices.

The motors have these red knobs on top that are usually covered; one is circled below:
Image

By winding this knob, you can set the headlights to whatever height is desired, as shown. However, the motors want to do a full revolution; they only turn in one direction, and stop at the bottom or top depending on some switches. (They work a bit like windscreen wiper motors in that respect, but with two positions where they can stop). The motors have an integral gearbox, and are joned to the headlights by an arm and rod. So make the lights pop up halfway, we just need to halve the arm radius, and shorten the rod by the same amount.

We were able to remove the arms with a bit of effort. When it went back together, we were a bit perplexed at why the two headlights were now out of phase (one popped up, one down). We tried disconnecting one motor while the other did half a cycle, then another half cycle, then a full cycle. Always out of phase. Image Finally it dawned: Weber had put the arm on 180 degrees out of phase Image It was readily rectified.

Modifying the headlights will be a future sub-project, perhaps for the long periods of time we will likely be waiting for parts.

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Post by juk » Wed, 11 Mar 2009, 06:59

coulomb wrote:
I guess it was a fairly standard install, but it sure taxed us all the way. Without the proper tool, it took a lot of "drifting" (whacking with a hammer) to separate the steering rod from the steering nuckle. We found that supporting the steering rod on a hydraulic jack helped.


The steering rods are best removed from the knuckle with a firm hit with your standard claw hammer or gympie on the side of the taper. This just pops out the ball joint and arm. It's the easiest way by far. This works for both the steering arm attachment and the lower control arm to the wheel assembly.

Personally i'd stay with manual steering. Do you know whether the weight over the front wheels is going to stay the same, get lighter or get heavier? Zeva might be able to assist you. You will find if it's going to get lighter that there is no need for power steering as the steering will get lighter anyway. Also if you put low rolling resistance tyres on the vehicle, it will get lighter again. The silica compound tyres help with this without sacrificing grip.
Last edited by juk on Tue, 10 Mar 2009, 20:05, edited 1 time in total.

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Post by coulomb » Wed, 11 Mar 2009, 07:49

juk wrote: The steering rods are best removed from the knuckle with a firm hit with your standard claw hammer or gympie on the side of the taper. This just pops out the ball joint and arm. It's the easiest way by far.
We went by a book which said to put the castellated nut on upside down, flush with the top of the thread, and tap on that. Well, it took a lot of bashing.

Are you saying to hit the tapered part of the steering knuckle? Just to jar things loose? I'm doubtful it would have worked on our 19-year-connected components, but we'll try it next time for sure.
Personally i'd stay with manual steering. Do you know whether the weight over the front wheels is going to stay the same, get lighter or get heavier?
Very likely heavier, by about 50-100kg, because of the (likely) 300kg of TS 40AHA cells, keeping the gearbox and clutch, and now power steering   [:D] . The front contender for motor and controller are 95kg and 55kg respectively. We don't know yet what proportion of the batteries will have to go in the front.

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Post by Electrocycle » Wed, 11 Mar 2009, 16:54

for the headlights, do a search for a "Pivot headlight controller"
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Post by EV2Go » Wed, 11 Mar 2009, 17:42

You did it the right way... When I changed Kearon’s power steering rack over to a manual rack I did it the same way. Only one thing I would suggest to make it easier for future tie rod end removals.

Do the same as you did... take off the castellated nut turn it over and put it back on so it is flush, but instead of hitting the nut, get a bit of hard wood (not soft because it absorbs the blow)and sit that square against the nut, now give it 1 or 2 sharp raps with the hammer and 99 times out of a 100 they will pop out without fuss.

That way it massively reduces the risk of buggering up the nut and the tie rod end thread, and you can give it a much harder hit without worrying. FYI you must hit the wood squarely and in line with the nut to get the best results.

Thought you might know the name of those things Andrew, I never was interested in doing that to my 180 so I never research it.
Last edited by EV2Go on Wed, 11 Mar 2009, 06:56, edited 1 time in total.

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Post by fuzzy-hair-man » Wed, 11 Mar 2009, 18:21

juk wrote:The steering rods are best removed from the knuckle with a firm hit with your standard claw hammer or gympie on the side of the taper. This just pops out the ball joint and arm. It's the easiest way by far. This works for both the steering arm attachment and the lower control arm to the wheel assembly.
I have done it this way on the mini and it works, I found it best to also try to lever the steering arm down as well, the risk with hitting the nut on top (or so I'm told) is that you could deform the threads and because it relies on the taper friction to stop it turning enough that you can do up the nut a damaged thread can be problematic as it just turns in the taper.

The idea was that hitting the side of the taper with a hammer deforms the taper enough to pop out the steering rods and avoids potentially damaging the threads.

Ball joint splitters also help like the one here (required sizes might be different):
Ball Joint Splitter
Last edited by fuzzy-hair-man on Wed, 11 Mar 2009, 07:34, edited 1 time in total.

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Post by coulomb » Wed, 11 Mar 2009, 18:31

EV2Go wrote:Do the same as you did... take off the castellated nut turn it over and put it back on so it is flush, but instead of hitting the nut, get a bit of hard wood (not soft because it absorbs the blow)and sit that square against the nut, now give it 1 or 2 sharp raps with the hammer and 99 times out of a 100 they will pop out without fuss.

I should have mentioned that we used wood; I'd never hammer metal directly. Perhaps our wood was too soft; I think it was Tasmanian oak (just what was to hand).

There is a cover in there that makes it hard to get a square hit.

Thanks to all for your suggestions.

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Post by EV2Go » Wed, 11 Mar 2009, 18:38

Yeah sometimes not being able to get a clean hit on it can be a bit of a pain. I have in the past still managed to do it while not hitting direct in line, as long as the wood is hard and square to the nut and you hold the other end of the wood firm, you can still hit it as close as you can get and have success. The trick is in the sharp rap of the hammer, slow heavy blows are not as effective.

Sounds like you guys are making some good progress...

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Post by juk » Thu, 12 Mar 2009, 01:52

Lads, i've done hundreds of these like this when i used to work as a mechanic. It is the proper way to do it without using a press. If you hit the thread you risk damaging the thread and the ball joint itself. The thread is meant to maintain constant pressure not impact pressure and you risk stressing it. The technique for removal is detailed here at about the 50 second mark.

http://www.youtube.com/watch?v=5PjkfDp8 ... r_embedded

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Post by Johny » Thu, 12 Mar 2009, 17:02

I use two hammers with a synchronised hit on both sides of the knuckle OR support one side with a hammer so you don't feel like you are destroying the steering arm bush.

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Location: Brisbane 1963

Weber and Coulomb's MX-5

Post by EV2Go » Thu, 12 Mar 2009, 17:13

"Without the proper tool, it took a lot of "drifting" (whacking with a hammer) to separate the steering rod from the steering nuckle."

He was removing the tie rod ends not the ball joints. Ball joints are best removing with a ball joint splitter but can still be done without one. Completely different technique to remove a ball joint.

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