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ASR Light on

From the diagram I posted before it would appear there is some form of "charging/filling port" at one end of the unit. If you remove the cover bolt you should be able to remove it. I would view any sign of major brake fluid leakage under the cover as suspicious? As Dieselman said it should be possible to regas the system thro this port. Any system capable of recharging the unit should have some form of pressure monitoring device which would allow you to check the residual pressure in the system. MB doesnt mention recharging the unit in its w124 workshop manual so it probably would have to be a specialist. The unit is filled to 100 bar initially which is 1400 psi ( 1bar is approx 14 psi) so it follows you must proceed with caution. To be honest I dont know how well these units last but it would have to be very good to retain 1400psi past moveable seals for so many years.
 
that is interesting stuff, have to take it step by step i think.. with lack of any proper diagnostics its all a bit hit and miss...

will try the brake switch on saturday and then move to the inside of arches if that doesnt work...
 
The other possibility that occured to me is if any of the ABS/ASR units have corroded/faulty/loose earthing straps.
 
OK Jay it works I can now send you all of the work sheets and how it works info plus anything else

I will send you the USB stick and the install disc, please PM me with your address then you can send it back to me
 
Right, changed the brake switch and......... no real difference..

The light still comes on very randomly... today it did not appear at all, but last night it came on after about 5 miles of driving..

It was an absolute pain to change the switch, very fiddly as its mounted right up behind the dash and is held on with 2 17mm nuts... very very tricky!

Anyway, so plan B is to wait for TV's usb stick and then get stripping... first port will be looking at the pump and accumulator... with no experience this should be fun... for example can i just remove these items to inspect seals? do i need to bleed the fluid after?
 
Almost certain bleeding will be required if the hydraulic circuits are broken by component removal. Some sort of pressure bleeding device will be required for these complex systems which will have several extra bleeding points on the ASR components.
 
yes i have noticed these nipples on the ASR and ABS units...

I do have an Eazibleeed thing that you connect to the tyres to provide pressure... never used it yet!

so how would i force the fluid through? i would need to make the pump work presumably?

maybe TV's 100 pages of info may shed some light...
 
jaymanek said:
yes i have noticed these nipples on the ASR and ABS units...

I do have an Eazibleeed thing that you connect to the tyres to provide pressure... never used it yet!

so how would i force the fluid through? i would need to make the pump work presumably?

maybe TV's 100 pages of info may shed some light...
Click to expand...

Jay,

I would use a pressure bleeder but make sre your resevoir is in good nick as it can split it. I have seen it happen on the older MB's.
 
Certainly the system would have to be running to bleed properly finally. That probably means the engine running?? I would read TV's instructions VERY carefully before starting. Theres a good article here about bleeding abs/asr systems http://www.aa1car.com/library/abs_bleeding.htm ---note carefully the warnings about depressurising the accumulator!!! It looks as if you have to know exactly what you are doing and the depressurising and bleeding sequences before attempting this .
 
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No worries... i ahve actually found a whole load of information in some paper manuals i had lying around and i feel more confident in giving it a go..

It seems the problem could lie in the following places:

- ABS/ASR Control Unit
- ASR Pump and various solenoids inside it
- ASR Pump Relay
- ASR Accumulator seals
- ASR pressure Regulator

I have no idea how im going to test these items but reading through these pages im at least confident of how to get them off the car... Once i do that, no idea what im looking for...

According to Grober, if the accumulator is shot i will find Brake Fluid, but thats the only real tip i have!..

Ideally i need someone who knows about ASR I and how to test it as im just poking in the dark..
 
Malcolm, many thank i received the stick..

there is one statement on page 3 that interests me:

If the ASR indicator lamp (A1e22) comes on when the
engine is running there is a fault in the ASR or in the
electronic accelerator pedal. ASR is inoperative, the
ABS continues to operate. If there is a fault in the
electronic accelerator pedal it is possible to continue
driving with reduced engine performance. The driver
notices this due to changes in the force required to
operate the accelerator pedal.

Now i do get a change in operating forces, when the light is on, i cant get all the way down with the pedal..

Does that mean my fault is with the cruise control unit?

I assumed that a fault in the ASR meant that it shut off the "electronic accelerator" aka cruise and hence the harder pedal...

Does this mean that if its not to do with the electronic accelerator then i wouldnt feel this extra force on the pedal?
 
electronic throttle

Jay I mentioned this as a possibility in my first post. It appears that reduced throttle travel + light on means the problem is with the electronic throttle/cruise control. I would think the problem is more likely to be in the actuator rather than the electronic throttle pedal position sensor but who knows? theres a post on Jim Forgiones site about a similar actuator problem . http://pages.prodigy.net/jforgione/MB_asr.html
and here on a rebuild due to wiring insulation breakdown problems
http://v12uberalles.com/throttle_actuator_rewire.htm

all sounds a bit expensive.:(

edit:- sorry it appears Malcolm mentioned JF 's site already.:o
 
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Yeh sorry Graeme, i thought that any fault in the ASR system meant the cruise was knocked off and hence the reduced travel...

hmm these are on W140's, now the unit looks very different on the W126...

Its very close to the radiator and where the top hose broke... hmmmmmm
 
Maybe its a good thing its not the same as the w140's --Might be better built? ;) Dont know how easy the older ones are to take to bits tho.
 
i had a quick look, there are two tears in the wiring loom outer.. the rubber seal where the wires go into the unit has also perished... i will be taking it apart later tonight ans ill see if i can spot anything as its easy to get to....
 
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