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Discussion Starter #1 (Edited)
ABS issue

Already in 2007, I observed the failure of the ABS system at speeds above 220km/h during road trips through Germany. Then still on a German temporary registration (5-days KKE), there was no need to comply with any vehicle inspection such as MOT, APK, TuV, MFK or whatever.

When I decided to register #231 on a Dutch registration I had to resolve the Dutch APK relevant issues for which we performed a pre-registration checkup in the winter of 2008. During those inspections, I discovered that the impulse sending wheels of the rear-wheel drive flanges were corroded as can be seen on the following picture.



This explains for the ABS failure at very high road speeds. However, for obtaining a Dutch registration in May 2008, this was a non-issue, as the RDW institute would not test the car under such extreme conditions. Since #231’s ABS system was fully functional within the legal speed limits in the Netherlands with a margin of 100km/h, this wasn’t a critical issue hence why I placed this issue on the back-log and planned to solve it in the winter of 2009/2010.

Then in June 2008, the engine failure came in between. With the following engine rebuild between March and September 2009, addressing the ABS issue was not important at all and remained low on the priorities list. Granted, I could have combined this the installation of the rebuild engine, but decided against that to obtain focus to the main objectives for that time.

With the running-in phase almost completed, solving the ABS issue is placed higher on the priorities list, especially since the speed at which the ABS warning light illuminates has lowered to about 190km/h on the speedo-meter. This reduces the margin to less than 70km/h from the legal limit. Although this still is more than enough to have my driver’s license being put through the ‘shredder’, but with the expected decay, it can become a relevant issue sooner or later and I’d rather resolve it in my own time and not with a fixed time-table to meet the criteria for obtaining the next road-worthy certificate.

I have just received the parts quotation from my dealer and although the drive flanges are just Euro 42,87 each, their status is backorder from factory. With other words, delivery time cannot be confirmed at the moment.

Appearance of the differential

Another issue that bugged me for a long time is the corroded diff-housing that deteriorates the otherwise very clean bottom of #231. Just like the ABS issue, this issue was placed on hold following the earlier mentioned engine failure.



Since the drive-shafts need to be removed for resolving the ABS issue, this is a good opportunity to improve the differential at the same time, therefore I plan to remove it as well according to the following scheme.

1: Remove drive shafts, inspect them and replace the boots of the universal joints if necessary.
2: Replace drive flanges and solve the ABS issue
3: Remove differential from car
3: Disassembly of the LSD, but leave the pignon-shaft in place because of the required pre-tension
4: Remove the rust and clean the housing.
5: Paint the housing with black POR15
6: Reassemble the differential, use new parts where necessary.

Front shimmy

I already have ordered two new lower control arms for the front suspension to solve the shimmy that I have experienced during recent road-trips. I have decided against aftermarket such as Meyle HD or Lemforder for two reasons.

1: Originality
2: I am not convinced on Meyle HD on my father’s A6 quattro were I preferred these over OEM. The ride still is a bit deteriorated by mild vibrations, even when new OEM shock absorbers with all the associated parts were installed soon after to eliminate other sources.

Front wheel arch liners

Following the experiences of member BMWWGN’s experiences with his recently acquired South African E28 M5, I decided to check the cover liners of the front wheel arches as well. This resulted in the decision to replace them on #231 as well, including the rubber seals. Fortunately, #231 doesn’t suffer from corrosion in the enclosed area behind these liners so there is no need to do some bodywork there.

All the required parts have been ordered; some of them already have arrived. I will update this thread from time to time and report the progress.
 

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Mine has the same ABS issue - the dash light comes on once the speed is above approx 30mph - caused by the hub teeth.

Luckily in the UK the annual test (MOT) doesn't involve getting the car up to speed, so it passes without problem :blink:
 

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Hi Raymond, y 535i had the same issue, i simply cleaned the hubs and treated them with some fertan, they became fine, and actully after 60k kms the abs doesn't worry about.
Fot the meyle, i have them under the 635csi and the 535i, they are good quality, in my opinion...
 

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Hi Curtis ,

Raymond is replacing part #10 , the lower control arm / wishbone .

The upper arm , part#5 , is sometimes referred to as the thrust arm and can sometimes be the cause of the shimmy , although in my experience , the lower arm is just as often to blame !

D
 

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Front shimmy
I already have ordered two new lower control arms for the front suspension to solve the shimmy that I have experienced during recent road-trips. I have decided against after market such as Meyle HD or Lemforder for two reasons.
You may only require new bushings, rather than the complete arm assy - a less costly repair.

By the way, the new exhaust system looks superb!:M5thumbs:
 

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Discussion Starter #8 (Edited)
You may only require new bushings, rather than the complete arm assy - a less costly repair.
True, but I don't suspect the bushings, but the ball-joints instead. I will confirm this after I have removed the old parts.

By the way, the new exhaust system looks superb!:M5thumbs:
Thanks; the old system lasted 23years, but some weak points forced its replacement.
 

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Been there & done that myself. Just replaced everything in the end as well as all of the ABS sensors. Not cheap but I will never have to do it again. Refer to my thread.

You should do the same. At some point parts will NLA.

Change all four wheel bearings & your ABS light will no longer flicker on at speed.

If your going to the trouble of removing your diff you may as well have it completly rebuilt. New input & output bearings.
Prices in pounds for all the required parts are on my thread.
 

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Discussion Starter #11 (Edited)
Friday afternoon, I picked up the new lower control arms that I have ordered recently to resolve the shimmy issue under braking. I will first replace the lower control arms position 1). If that doesn’t help, I will replace the thrust arms (position 2).



The reason why I am not replacing the bushings is rather simple. With the shimmy issue, I do not suspect these are to blame. Instead, I suspect that one of the ball joints have failed. These parts are integrated into the control arms, and cannot be bought as separate parts.



Next to these parts, I will also replace the associated nuts and bolts, some of which I already have on stock due to the minimum order quantity of these parts at BMW. Unfortunately, I didn’t order the new crown-nuts for the ball joints; I will do so tomorrow. With the new control arms, I also get new bushings so that I don’t have to use a hydraulic press to fit them.

The net price for the complete parts is slightly less then 127 Euro ex VAT per side. Add to that the usual discount and I end up at around 100 Euro ex VAT per side. This is more then after market Meyle HD, but as said in the kick off post, I haven’t been convinced about their quality thus far.



Whilst writing the replacement plan, I got stumbled in the E28 repair CD that does not mention the exact tightening specs for the E28. For that, I turned to an old friend and BMW Guru, member ‘Billie S38’. I will quote them here for reference:

Lower control arm:
- Ball joint: 85Nm
- Bushing to engine subframe: 78Nm

Thrust arm:
- Ball joint: 85Nm
- Bushing to chassis: 130Nm

Last but not least, I also received the new wheel-arch liners that I decided to replace as well after reading member ‘BMWWGN's’ thread about his SA E28 M5.



These liners are just 5,53 Euro per piece (ex VAT) before discount, so one cannot really bother. This also applies to the rubber seals that are about 1,50 Euro more. Member ‘BMWWGN’ painted them in the matching color, but I have yet to make up my mind.
 

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My covers came in grey as per your old ones which are a nice contrast with the black paint of my car. It's good that parts like these are reasonably priced from BMW.
 

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Discussion Starter #13 (Edited)
I picked up the largest part of the required parts for the overhaul of the differential this afternoon. After disassembly, cleaning and finishing the cast iron differential housing, the differential will be reassembled with new seals.



Although the output shafts of the E28 and E34 are very robust, the rubber boots will perish sooner or later exposing the expensive constant velocity joints to the hostile environment of the outside world we live in. After twenty-five years, it is wise to replace the boots and give the constant velocity joints a proper clean and a fresh supply of grease. BMW offers a complete revision set including the required grease and hylomar adhesive. The set costs 42,75 Euro ex VAT per piece; four are needed for both outputs shafts. Rest assured that a new output shaft is much more expensive then that.



BMW also listed a sealing set for the differential, but my parts catalogue indicated that only the single parts could be ordered. The following picture shows the seal and the circular clip for the output shaft.



I plan the tackle this job between Christmas and Boxing Day as I need to finish the E32 first that returned from a week stay at the body shop to repair the sill damage that I discovered some time ago. The rust is the result of poor craftsmanship during a previous repair before we even bought the car (1998.



After I removed the filling that at some spots was over 5mm thick, the true extent of the damage appeared.



Repairing such damage goes beyond my capabilities so I outsourced the work to the body shop of my brother in law. The final result looks very nice; bear in mind that the sills are covered by plastic liners; oops these need replacement as well, which is $$$ for seven series parts.

 

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Discussion Starter #14 (Edited)
Last week, I have finished the E32 by installing the new sill-covers, after which the lift was free for the E28. The E32 has some issues left, but none that can be solved off the ramp. As the snow that has fallen last month, hasn’t melted due to the low ambient temperatures, there is a nice layer of ice in front of my workshop, due to which it was quite a hassle to get the E28 on the lift. When driving on the lift with the front wheels, the rear wheels were still outside and spinned on the centimeter thick layer of ice during which the car’s rear jumped sideways. Eventually, I took a rolling start to get some momentum and that did the trick.

I started with removing both driveshaft’s These will be overhauled with new boots and a new filling of grease for the coupling joints.



With both driveshaft’s out of the way, I was able to remove the final drive. This is rather easy, but the four 19mm bolts with which the final drive is bolted on the rear sub-frame were tight and I needed a breaker bar to loosen them. Eventually, the bugger came loose, but with a heavy cast iron house, lowering the damn thing didn’t came without protest from my back.



The plan is to get it back in a visual excellent condition to match the rest of the drivetrains excellent visual condition. The bearings themselves don’t need replacement, so I will just remove the rust and treat it with POR15 before reassembly with new seals.

With the differential out of the way, I have a better position to inspect the cars underside. There is only some surface rust on the sub-frame that will be removed and treated with POR15. There is no need to replace the sub-frame’s bushings; these were all replaced just 7000km ago by a main dealer and are all in excellent condition.



To diagnose the front wheel shimmy, I have removed the front wheels so I can remove the strut assembly. The plan is to replace the lower control and thrust arms and have the struts themselves sandblasted and powder coated. This also allows me to replace the protective covers of the shock-cylinder and inspect the strut mounts.

 

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Discussion Starter #15 (Edited)
Yesterday evening, I removed the right-front strut assembly. Although this is relatively straightforward, bear in mind that unbolting the various nuts and bolts require a significant amount of force and thus your cars should be safely positioned on a ramp. Never, ever try to do this from underneath a car.



I have yet to disassemble the strut-assembly for which I need spring-compressors. Again, never ever remove the top not holding the upper strut-mount without these. This will cause serious injuries due to the energy stored in the compressed spring.

A first analysis revealed a significant amount of play in the rotational part, both in axial and longitudinal directions. This could be the cause of the shimmy under braking, but for a comparison, I have to remove the left-strut assembly first. Anyhow, these parts will be replaced, together with all the associated parts.



Unbolting the ball-joint nuts from the strut-base is rather straight forwards, but even with a ball-joint depressor, I wasn’t able to remove them. Therefore, I will remove the entire base-plate with the thrust arms and lower control arms as well and move them to the bench were it is safer to apply a lot more force.

My first thoughts is that the ball joints have lost their stiffness significantly, but for a comparison with the new part, I have to wait until I have removed the old part.



Apart from some surface corrosion, the strut towers are in fine condition. They will be cleaned and treated with Caprotec RX5 before installing the reassembled struts.

 

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Discussion Starter #16 (Edited)
Last week, I have removed the left strut, and both strut-base plates with attached control arms. The removal of the strut itself only requires half an hour. Disconnect the ABS sensors, guide their wiring through the inner fender, unbolt the brake caliper from the strut and remove the brake-hose from the strut as well. Then loosen the three 17mm bolts with which the strut is connected to the base plate and loosen the three 13mm nuts that hold the upper strut-mount to the strut-tower.

One word of warning though; unbolting the three 17mm bolts requires a significant amount of force. Make sure that your car is safely jacked up with the appropriate means. I cannot emphasize this hard enough as no car is worth risking your life for.



To remove both thrust arms, I removed the front stabilizer bar and one strengthening bar. This is required to gain access to the 22mm bolt and nut with which the thrust arm is bolted to the front beams.



On the right side, I also needed to remove a heat-shield, this is rather straight forward and therefore, I didn’t make a picture.

I already had bought the lower control arms as a possible suspect of the shimmy, but decided against ordering the thrust arms as I wanted to analyze the individual parts first. As can be seen on the following picture, the left thrust arm is made in 1989, and thus most likely installed in the same or following year. Clearly visible are the cracks in the rubber vulcanization of the bushing.



The right thrust arm is of a more recent date (see following picture), but without any OE or manufacturers markings visible, I can only conclude that this is an after-market part of unknown origin. As a corrective measure, I will replace both thrust arms and bushings with new OE parts.



The next step is the disassembly of the struts, To remove the springs, a special tool is required to secure the springs when the strut mount is removed. Without this tool, the compressed spring will release its energy to the strut mount launching it into the air with a force that is enough to cause serious injuries.



Ideally, the three compressors are placed at an angle of 120 degrees from each other, allowing for an evenly compression of the spring. The spring can be compressed by turning the screws with a wrench or ratchet until the spring is compressed enough to loosen the top nut with which the upper strut mount is bolted to the shock absorber. The following picture shows the deteriorated seal of the strut-mounts bearing exposing its ball-bearings.



As both spring mounts show a similar sort of damage and have ~1mm of radial play and some axial play, it is safe to conclude that this is the main cause of the shimmy. Both parts will be replaced with factory OE parts. Another discovery was the missing lower-spring pad on the left strut indicating a poor quality repair in the past. The following picture shows the lower spring pad of the right front strut still on the spring.



With both springs removed from the strut, I have access to the nut that secures the shock-absorber in the spring.



My first impression is that both shock absorbers are in fine condition. They have a similar resistance to the new shocks that I installed in my E34S M5 a few years ago. But a final analysis can only be made after I have removed the inserts., something that is scheduled for next week.
 

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Great pics and write up as usual Ray .

That second thrust arm ( R/H/S ) appears to have the small triangular owl / triangle Lemforder motif and a BMW OE bush , if my eyes don't deceive me . Regardless , new arms with bushes are relatively cheap and offer huge returns in terms of steering response .

Meanwhile , if you believe that the front dampers are good , with no obvious signs of failing or leakage , then I wouldn't go to the trouble of removing the collar nut and damper , but simply renew the spring pads / bump stops and top mounts . Combined with the new upper and lower control arms , your car will feel like it's on rails .

One other recommendation would be to renew the 3 x 17mm bolts that secure the strut plate to the strut , as these have been known to fatigue and are in no way as durable as the thicker E34 variant .

Roll on the spring , Ray , when you can get out and really enjoy this beauty !

D
 

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..if you believe that the front dampers are good , with no obvious signs of failing or leakage , then I wouldn't go to the trouble of removing the collar nut and damper , but simply renew the spring pads / bump stops and top mounts . Combined with the new upper and lower control arms , your car will feel like it's on rails.
I think Ray's plan is to have the struts and springs blasted and powder coated, in which case it will be necessary to remove the damper inserts.:M5thumbs:
 

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I think Ray's plan is to have the struts and springs blasted and powder coated, in which case it will be necessary to remove the damper inserts.:M5thumbs:
What was I thinking ?

I should have remembered that there would be very little chance that Raymond would leave anything looking used on his car !

My mistake........
 

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Discussion Starter #20 (Edited)
Hey D,
The nice thing about separating the analysis from drafting the plan of approach is that one can adjust the basic ideas :cheers: That is why I am always open to good suggestions and your suggestion to leave the shock inserts and collar nuts in SITU is a damn good one. After going back to my top level overview, I reconsidered my objectives:

1: Appearance
2: Functional
3: Confidence

If my only objective is the visual appearance (1), I could have spared myself the hassle of disassembling the struts any further. From a functional perspective (2), it appears that there is no need either.

From the third objective, confidence, I still haven't found all the answers to the questions that I have. Given the visual condition of the collar nuts, I suspect that the strut inserts have been replaced in the past before. This raises the following questions:

1: What is the origin of the shock-absorber inserts?
2: What is the date-code of the shock-absorber inserts?
3: Have they been installed with cooling liquid (oil or glycol) in the struts or without?

To answer these questions, I have to remove the collar nuts and thus the strut inserts, so after giving your suggestion some thought, I have decided to pursue with my original plan to remove the inserts. However, I have yet to make a decision about improving the visual appearance of the struts themselves; to blast and powder coat them, I also have to remove the hub with the bearing. I didn't realize that during my brain storm session some time ago.

I have to admit that this is the strength of this forum; people that are actually give pro-active input. Even when their suggestions aren't 100% followed, the new viewpoints could change the plan of approach or add other arguments that I haven't seen before.

In that respect, your advice to replace the 17mm bolts gives supports my decision to replace these bolts as well. I already have these bolts on my project-stock for the very same reason that you mentioned.
 
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