Odd brake issue, any ideas?

[Rybky]

Since having the shocks replaced and the ECS Stage 2 refresh kit fitted last week my car has developed a strange issue. A few times now when I have been reversing at low speed on full left lock (have not tried on right lock) I lose brake pressure, not completely but the pedal becomes really spongy and goes down about half way before doing anything.

The first time this happened I nearly put the car through the back wall of my garage!

I have had no issues while moving forwards, pedal pressure remains constant while standing and there are no warning lights on the dash when it occurs.

I took it back to the guys that did the work and they were very good, had it up on the ramps and checked everything around the front end that they would have touched. They could not think what would be causing that behaviour. Brake fluid level is good and there are no signs of leaks anywhere.

Any ideas?

Adam

[Transporter]

I don't know if they disconnected brake lines or not. But try activating ABS several times (drive on something slippery and brake hard, side of the road with gravel on it or grass, could do it with one wheel only) and retest if there is any improvement.

[Rybky]

Yes they did have to disconnect the brake lines when they fitted the refresh kit (not sure that is really necessary??), when I took it in this morning they wondered if it might be ABS related so I will give your suggestion a go!

Thanks,

Adam

[Manaz]

Yes they did have to disconnect the brake lines when they fitted the refresh kit (not sure that is really necessary??), when I took it in this morning they wondered if it might be ABS related so I will give your suggestion a go!

Thanks,

Adam

Definitely necessary. I'd be wondering if there weren't an air bubble in the lines...

[Rybky]

Definitely necessary. I'd be wondering if there weren't an air bubble in the lines...

That thought crossed my mind but I would expect that to be a problem even going forwards, this has only happened when reversing .... so far!

Adam

[Jarred]

should feel bubbles all the time, if there was some.

If it's related to full lock left, I'd suggest something might be getting squeezed maybe? is the brake line hooked on anything etc, able to get squished by something when you turn to full lock? It's a long shot but worth a go.

same goes for anything ABS realated that's connected to the brakes., check nothing's binding, caught up, etc. Long shot, but that's what I'd check.

[Rybky]

should feel bubbles all the time, if there was some.

If it's related to full lock left, I'd suggest something might be getting squeezed maybe? is the brake line hooked on anything etc, able to get squished by something when you turn to full lock? It's a long shot but worth a go.

same goes for anything ABS realated that's connected to the brakes., check nothing's binding, caught up, etc. Long shot, but that's what I'd check.

That is a good suggestion. The guys this morning did take the wheels off and check everything thoroughly but I guess with the wheel off it might not be so obvious if the wheel is actually interfering with something. Might check this myself over the weekend if it persists.

Adam

[Mr_Bob]

could be a dodgy ABS sensor?

if it thinks that it has locked up at one corner, it might be backing off the pressure in the system to regain traction
This could happen due to speed differential between left and right at full lock


Do you get reasonable pedal feel when they do start to work?

[Rybky]

could be a dodgy ABS sensor?

if it thinks that it has locked up at one corner, it might be backing off the pressure in the system to regain traction
This could happen due to speed differential between left and right at full lock


Do you get reasonable pedal feel when they do start to work?

Hmm, might even explain why it occurs only in reverse? They would have had to disconnect the sensor when they did the work I guess, can they be connected up wrong?

Pedal feel is perfect all the rest of the time.

Adam

[craig_the_german]

Hi,
This may sound silly but just check that the brake hoses go around the suspension struts the right way. When I bought my car, the previous owners had some work done around the front suspension/brakes and when they had it reassembled they passed the hose feeding the caliper the wrong way around the strut so if the steering was turned the hose was actually pulled tight against the strut possibly to the point of almost crimping the hose off.

While driving straight - no problem but if you were to try a reverse park - crimps the hose off....

Just a thought

[Rybky]

Hi,
This may sound silly but just check that the brake hoses go around the suspension struts the right way. When I bought my car, the previous owners had some work done around the front suspension/brakes and when they had it reassembled they passed the hose feeding the caliper the wrong way around the strut so if the steering was turned the hose was actually pulled tight against the strut possibly to the point of almost crimping the hose off.

While driving straight - no problem but if you were to try a reverse park - crimps the hose off....

Just a thought

That would certainly fit with the symptoms I am having! I will definitely check that out tomorrow, thanks!!

Adam

[Jmac]

Hi there, so you havent lost all pressure, air in the lines would most likely be all of the time mate. The full lock thing seems significant here, i would definately check what Craig the german says mate, ive seen a few now that have been in shops and for some reason the flexi pipe gets routed wrong and if its on full lock you could be choking it, as you have half a pedal then its part of the circuit thats affected , not all of it so that makes sense to me
Good luck let us know what you find
cheers
Jmac

[Rybky]

I checked both brake lines today and on both sides it is routed behind (engine side) of the struts and is nowhere near touching anything on full lock. So it looks like we can rule that one out.

Have not tried the ABS activation idea yet and maybe a diagnostics check will show if an ABS sensor is playing up.

Adam

[Jmac]

Abs activation would cause the pedal to pulse though. You need to have it doing it then clamp off the lines till the pedal goes hard again, this would pinpoint the offender
Cheers
Jmac