Thread: Brake Failure ABS problem?

Yeah, I thought the dodgy fuse idea was probably too good to be true. Guess I'll be off to the workshop soon to get my sensors checked.

Originally Posted by Bazzle218

I posted this last week with no replys

(1996 300TDI ABS.

I have fitted new rotors and pads but have noticed an annoying problem. When I'm driving i have one good application of brakes and then they are crap. Peddle goes hard like there is no vacuum boost. Now I have read the good oil and other posts. If I let the peddle off for a bit and try again its fine for another application. In normal braking it should not be a problem but in the bush who knows. The one-way check valve works ok; I have pulled off and checked that the vacuum pump is drawing. Any thoughts or any hints What about fitted an aftermarket vacuum reservoir or am I dreaming. This problem was there before the rebuild so not sure if it’s a problem or just a Landover thing.)
Thinking its the same problem. How does one bleed the abs pump? I have also asked this one with no responce . I'm assuming that it can be all related

i have this exact same problem,
fitted new front sensors as diagnosed by ricks,
abs system works when tested by braking hard with two wheels on the dirt other two on tarmac.
i also have this problem with the fuse removed.

a typical example of this at it's most annoying, is when i attempt to join the traffic on the motorway on ramp,
you know the scene,
check over your shoulder and work out where you will fit in -merge,
and accelerate,
look forward to check where the hiundi excel is,
look over shoulder to check where you will fit in again,
look forward and find that the excel is stopping bugger,
begin braking,
woo, she's slowing right down,
press harder on the pedal,
this is where mine is really bad, as at this point i cannot press hard enough to increase braking, the pedal is solid and the car sails along as if nothing happened, still slowing, but not any faster,
this is where i begin looking for space to go around the excel, as the big green disco is going to destroy the excel if i don't steer around it.

and if that isn't enough fun, try it with a heavy trailer hooked on!!

things i have done so far-
bled brakes
checked that the pistons will easily move past the current pad thickness [tricky one to check - push pedal without pads ]
checked abs works,
checked vac pump works [300tdi]

does anyone know what vacuum the vac pump should pull?
and any suggestions?

A vac reservoir is your friend. Hook up a standard vacuum gauge to your booster and see how slow it is to recover. I have a vacuum tank on one old vehicle which gives me 3 full uses of the brake with power assistance without an engine running. Smaller ones were often fitted to vac trailer brake systems and should be available from PBR still. I have some used disposable argon cylinders of 1 litre capacity which look like they would make great vac reservoirs. They have a 1/8 BSP thread in the top when you manage to unscrew the valve that they come with.

Originally Posted by Bazzle218

How does one bleed the abs pump? I have also asked this one with no responce

I have bled my whole system (ABS) with no problems at all, I used a gunson bleeding kit which pressurizes the whole system and you can bleed each wheel in on smooth continuous movement and without an assistant (who keeps disappearing to do things like washing)
My thought is that bleeding the regular way with someone pumping the brake pedal, gives air bubbles the opportunity to stay in the system and so cause problems.

Gunson | G4062 | Eezibleed Kit

You can also use a vacuum bleeder, a more expensive piece of kit that many mechanics would use.

that looks to be an easy to use jigger, not sure if it is available in aus., but there are similar things here.

does anyone know what vacuum the vac pump should be capable of making on the 300 tdi?
it doesn't appear in any of the manuals i have.

bee utey, surely the car was capable of performing when it was younger, why would it need a vac tank now?

i want to know what is wrong, and fix that.

In response to the original question re ABS faults and brake failure can I suggest as others have previously the only sensible solution is to seek some professional help in diagnosing the problem.Mine scared the Sh$! out of me once and I didn't give it the chance to do it twice.I was very lucky that I was only going slow, around 50Km/h, and wasn't trying to stop at an intersection.No matter how hard I pushed the pedal it just jacked back as the ABS fired and the brakes did nothing to slow the vehicle down. Once the ABS light comes on the brakes cant be considered safe and every time you use them its a roll of the dice.My problem was as simple as a faulty front passenger side sensor which was replaced and it has been faultless since.It was a few hundred dollars to get diagnosed and replaced by a LR service center.
Yes I may have eventually worked it out myself through trial and error but how many lives do you want to put at risk while you play around not really knowing what your doing.

thanks, '98, i too have replaced both front sensors, the abs works fine,

it's still just got no brakes, pedal is way to hard for the retardation that happens.
but everything else works as advertised,
no caliper problems, just no brakes.