21 Turbo ABS unit in UK

[21Tpt]

Hello,

I've noticed that right hand drive 21 Turbo's have a different ABS unit compared to left hand drive ones. LHD have an accumulator sphere and from pictures that i've seen, RHD models doesn't have this kind of unit.

Is this true or am i just mixing things up?

Thanks

 

[DaveL485]

You are correct. The Brake masters are different on RHD-LHD, as are a few other bits.

 

[21Tpt]

My abs stopped working and brake pedal is harder than it used to be.

I assumed the problem was in the accumulator thing and i've replaced it. Also i replaced one wheel sensor that was malfunctioning.
Still doesn't work, but warning light is off now. Sometimes when i go over bumps on the road the yellow light flashes for a bit.

Anyone has had this problem?

 

[DaveL485]

My abs stopped working and brake pedal is harder than it used to be.

I assumed the problem was in the accumulator thing and i've replaced it. Also i replaced one wheel sensor that was malfunctioning.
Still doesn't work, but warning light is off now. Sometimes when i go over bumps on the road the yellow light flashes for a bit.

Anyone has had this problem?

Does the accumulator pump work? When you start the car up first thing, or if you pump the pedal a bit with the ign on, you should hear it kick in to life and buzz away. Its the thing under the expansion tank with the black ball on top (the black ball is where pressure is stored).
A hard pedal usually indicates the accumulator isn't working properly. The yellow ABS light and the red handbrake light will come on if the accumulator is under pressure. If it's just the ABS light, then thats a problem with ABS only, if it comes on and stays on from first start its a sensor, if it goes out and comes on after some driving or over a certain speed then its usually a deteriorated or damaged target ring. If the handbrake light is on on its own with the handbrake off that means low brake fluid level.

What car is it? 2wd, Quadra, year/Phase?

 

[21Tpt]

The car is a 2WD from 1989, Phase 1. One of the last produced before 2nd phase came out

When i start the car i hear the buzz and if i depress the brake pedal several times it comes on again. Before i replaced the accumulator cylinder, every time i put the brakes on, the pump would start up. Now it only happens once in a while. So i think the accumulator pump is working well.

The handbrake light never comes on. If i get a bump/hole in the road the ABS light comes on for a bit and then goes away. Speed up to 90 mph doesn't make any light turn on (i don't remember the last time i drove over that speed )

How about the hydraulic unit where the outlets for the front left and right and rear brake fluid are located? I saw somewhere some images of a guy that disassembled that unit and everything was corroded inside.

 

[DaveL485]

At least its a 2wd so a new master will be much easier to source should you need to.
I've never seen some do the bump in he road thing. Suggests a loose connection, check all your sensor plugs are secure and dry. Also check the abs computer is secure and dry too, under the passenger seat.
Is the pedal still super hard now the accumulator is working?

 

[21Tpt]

I will run some checks with a multimeter and clean the sensors and rings. But yes the pedal feeling didn't change much with the new accumulator cylinder.

The ABS unit you have in UK versions seems to be a improved generation of the system. Does it have a regular brake servo?

 

[DaveL485]

I will run some checks with a multimeter and clean the sensors and rings. But yes the pedal feeling didn't change much with the new accumulator cylinder.

The ABS unit you have in UK versions seems to be a improved generation of the system. Does it have a regular brake servo?

Then the new accumulator isnt working then surely. It shouldn't feel superhard and bouncy on the pedal.

No, UK cars don't have a servo. Same electronic system, just positioned differently.

 

[21Tpt]

But if i hear the pump working and no lights come on when i brake, and if i depress the brake several times the pump works again, doesn't that mean the accumulator is working?

 

[DaveL485]

But if i hear the pump working and no lights come on when i brake, and if i depress the brake several times the pump works again, doesn't that mean the accumulator is working?

Yes, but if your pedal is bouncy hard something must still be wrong... unless the pedal is fine and its just that you dont have anything to compare it to?

Can you lock the wheels in the dry without doing a He-Man stamp on the pedal?

 

[21Tpt]

Yes, if i press it not so gently it will eventually lock the front wheels. Maybe you're right, i don't have another one to compare and my memory about what it used to be when the ABS worked is probably wrong.

Phase 1 if i recall correctly doesn't have a way to diagnose ABS problems through the socket connector in the engine bay.
So i guess i'm going to measure all the values in the ABS ECU connector to see if they are normal.
But i'm not so sure if this method tells everything to perform a full diagnostic.

Is it possible a malfunction of the ABS ECU? Or are they "bullet proof"?

 

[DaveL485]

Testing the sensors with a resistance meter has always worked for me. One usually shows an obvious difference. With your intermittent issue check the cables are retained properly around the wheels and haven't come loose and rubbed on something moving causing a short.
I have never come across an ABS fault with an ECU (yet). Always sensors or targets.
You are correct the 2wd doesn't have the self diagnosis function. Only Quadra.

The times I have tested cars with failed systems I found the braking was dangerously hard, and needed a massive amount of pedal force to brake. If you wouldn't deem it unreasonable force then maybe its OK. Where are you located? Anybody close to you on here?

 

[21Tpt]

I don't have to do massive force to brake. It's just not that progressive. Between up position and locking wheels maybe it goes down 1.... 1 and a half inches.

I'm from Portugal and 21 Turbo's are getting scarce around here, so i don't know anyone that owns one.

Thanks for the help.

 

[DaveL485]

That sounds OK then

I know we have a member here in Spain with a 21, @SINKY I think, not sure whereabouts though! Spain is a big country lol

 

[21Tpt]

I'm on the west coast so it would be a long drive to the border and as you said, Spain is a very big country

 

[la21t]

Sorry Dave but you agreed with him when he said 'the UK car doesn't appear to have an accumulator sphere'

You OK? Lol
If you want one posted to you, I'm sure we can sort something out among us.

 

[21Tpt]

Sorry Dave but you agreed with him when he said 'the UK car doesn't appear to have an accumulator sphere'

You OK? Lol
If you want one posted to you, I'm sure we can sort something out among us.

So you're saying that there are some models in UK with the black accumulator cylinder?

 

[DaveL485]

So you're saying that there are some models in UK with the black accumulator cylinder?

Yes, sorry I phrased my reply badly. All UK Turbo's have the accumulator but the setup is very different.

The UK cars have a separate Master Cylinder and Accumulator pump (with the black sphere). The Brake Master sits on the right side (as you sit in the car) (Yellow), the accumulator with the black ball sits on the left under the expansion tank bolted to the bulkhead/chassis (Green arrow)
There is an unpressurised feed from the bottom of the reservoir to the accumulator and then a pressurised line back from the accumulator to the master cylinder. They are entirely separate units.



In the LHD model the whole thing seems to be one complete unit sitting on the left side, with the expansion tank on the right. Ive never removed one so they might separate, they might not....maybe you could tell us that?

 

[DaveL485]

Found a picture of the unit in position...looking down with the expansion tank moved out the way, this is when I changed the one on @quadrastu's car
Ignore the additional black round thing on the left, thats additional kit for Quadra only, it's the pneumatic difflock controller. 2wd doesnt have that. Look at the left half of the pic.

 

[21Tpt]

Interesting! Never imagined they would separate the thing on opposite sides of the car.
If i recall correctly, i think the last ones from 1993/94 have a newer version of the ABS unit without the accumulator.

Well thank you for the information