20 year old brake system

my father in law has G reg Vogue turbo D, it has an early anti lock brake system, with 4 pot calipers on the front and an electric hydraulic servo pump( not actually a servo as such). he recently towed a car on a trailer and found his car was pulling severly to the right when braking. he has tracked it down to a problem with some electronic control device that this pump thing is attached too. it has about 8 outlets to the brakes and it dont seem to be allowing the fluid to flow to the left caliper properly. he has sourced another unit and fitted it, but now the electric/hydraulic pump doesnt seem to be working properly and isnt creating enough pressure.
has anyone got some tech info on this system that would help him or an idea where he can get a decent replacement part that aint gonna break the bank

Yup.... it needs bleeding properly!
If you dont do it 'to the book' which is a complicated little procedure running from valve block to caliper and back again, you dont get all the air out, and the booster unit runs dry and burns out!
Oh.... and you have to turn the ignition off and depressurise the booster before hand, something like 30 pumps on the pedal or somthing like that, or it keeps the air squashed in the top so you cant get it out.
DO NOT try an 'pump it thru' ........ use a pressurised bleed kity, like an EZ-Bleed
Follow the book, and you wont go wrong.

Teflon nailed that one. I've done the same job on my RRC with no problems but it is essential you follow the brake bleeding procedure. It will take a little bit of time and LOTS of brake fluid.

The ABS system on these is very good but a nightmare if they start playing up. Another thing you might want to check is the condition of the callipers, if the seals are shot and the pistons corroded, that might also cause the vehicle to pull to one side. You can get service kits for the callipers but follow the manual procedures if doing an overhaul.

Teflon said:

Follow the book, and you wont go wrong.

Click to expand...

which book are we talking about? its the in law car and i dont think he has even a haynes for it

classic kev said:

It will take a little bit of time and LOTS of brake fluid.

if the seals are shot and the pistons corroded, that might also cause the vehicle to pull to one side..

Click to expand...

calipers have been check and cleaned but withy no success

graingermouse said:

which book are we talking about?

Click to expand...

We are talking about "the book" - the official workshop manual. Don't panic, do a search in Landy Zone for RAVE, then download the appropriate book and burn to CD.

Then tell him he's an effing pidlock!
You dont go effing about with safety critical ruddy electronic brakes without a chuffing Haynes manual!
£20 at Halfords Tell him to go get one, read it and follow the instructions!

While he is at Halfords tell him to pick up an easybleed and apply about 10psi to the resvoir when he bleeds it - not more,it helps loads.

BTW, has who ever checked for a blink code from his ABS? If there was a problem in the valve block I would have thought the warning light would be making its presence felt?

Apart from that, have to agree once more with Teflon - don't screw with the brakes unless you have some idea what you are doing with them.

It also occurs to me that pulling under braking when laden with a trailer may not necessarily be all brake related, steering/suspension wear, tyre pressures even could also be an issue so it might be sensible to get the car up on a ramp and thoroughly looked over. Of course, that's just another point of view.

eightinavee said:

While he is at Halfords tell him to pick up an easybleed and apply about 10psi to the resvoir when he bleeds it - not more,it helps loads.

Click to expand...

You're not wrong I know!

classic kev said:

BTW, has who ever checked for a blink code from his ABS? If there was a problem in the valve block I would have thought the warning light would be making its presence felt?

Apart from that, have to agree once more with Teflon - don't screw with the brakes unless you have some idea what you are doing with them.

It also occurs to me that pulling under braking when laden with a trailer may not necessarily be all brake related, steering/suspension wear, tyre pressures even could also be an issue so it might be sensible to get the car up on a ramp and thoroughly looked over. Of course, that's just another point of view.

Click to expand...

he's very clever mechanically, and whilst his forte is vintage and classic motor bikes he is pretty clever with most things with an engine in. he has also had 2 mechanic friends take a look at it , with scratching heads being all they could do. i think the breaking under load actuallty highlighted the problem for a vehicle that doesnt do many miles on a journey and then only around town.

im gonna let him know what you have said, and im down loading the manual as i type, fingers ccrossed and thanks for the advice

just spoke to him, its now not pulling to one side, but the pump isnt keeping the pressure up, the light goes out but the pump doesnt cut out coz its not getting up to full pressure.

he has read up on the system in a haynes manual, in the library

graingermouse said:

just spoke to him, its now not pulling to one side, but the pump isnt keeping the pressure up, the light goes out but the pump doesnt cut out coz its not getting up to full pressure.

he has read up on the system in a haynes manual, in the library

Click to expand...

Wheel bearings?
Pressure accumulator?
How old is the brake fluid?

classic kev said:

Wheel bearings?
Pressure accumulator?
How old is the brake fluid?

Click to expand...

he has used 7 litres of brake fluid in the last week, dont see how wheel bearings would affect the pump.

possible pressure acculuator, will mspeak to him

graingermouse said:

he has used 7 litres of brake fluid in the last week, dont see how wheel bearings would affect the pump.

possible pressure acculuator, will mspeak to him

Click to expand...

Simple - wheel bearing allows hub and disc to move, pushes pistons back so when brakes operated poor pedal. The system runs the pump to boost the pressure squeezing the pistons so the pads grip the disc and this then centralises the disc so the brakes work:doh:

If you've used 7 litres of brake fluid in 1 week there is clearly a leak and the car shouldn't be on the road. It seems quite obvious with that piece of info the problem is a leak in the system and the pump is running to try and maintain pressure. Get the source of the leak identified and fixed; pronto.