405 brake problem

dvhttn · Post by **dvhttn** » 08 Oct 2005, 19:39

Hi,

Small brake problem you guys may be able to help me with. Oh, and thanks to
those who took over the Forum - stupendous job!!

I've recently replaced ALL 6 flexible hoses on my 405 1.8TD. It then failed
the MOT (in part) on rusty rear solid brake lines. As I don't have a pit or
ramp I got the local garage to replace them for me. They came back and said
'we can't bleed the brakes - the master cylinder is shot. When you keep your
foot on the pedal it gradually creeps to the floor'. Hmmm. They were 100%
certain that it was gone so I got one from GSF (39+vat whereas they quoted
me 69+VAT .... ). When I handed it over there were 2 mechanics there who
both said '100% master cylinder'. Guess what? Next day - we can't bleed the
brakes .... same symptoms.

They had called the Peugeot helpline and talked to R&A Engineering in
Reading. They thus came to the conclusion that the ABS pump was faulty. I
drew the line at replacing this as it wasn't needed for the MOT. I also only
paid them an extra 20 squid over and above replacing the lines as they had
been so adamant that it was the master cylinder at fault.

Now the problem is still there - apparently if you have your foot on the
pedal with the engine off it stays rock solid. With the engine on then it
creeps to the floor. The same with all flexible hoses clamped off. Is it
likely to be the ABS unit? I have the Bendix Additional ABS on the car.
Disks back and front with Girling calipers. No leaks.

The ABS also has a problem in that just as I'm coming to a halt there is a
pulsing through the pedal. It has been suggested that faulty sensor/wiring
could cause this and I do have a broken sensor which causes the ABS light to
come on 1 time in 5 (wired to the ignition light for the MOT ... ). But
could a faulty pump also cause this ...?

My first port of call will be to replace the sensor (when I can find a cheap
enough source for a new one!) but does anyone have any more information o
the problem???

Thanks in advance!

AndersDK · Post by **AndersDK** » 08 Oct 2005, 23:40

Dave -

Try rip the ABS circuit connector on the ABS valve block and drive the car a couple of days. The ABS system must NEVER do strange things to the brakes. Its only supposed to be an add-on preventing the wheels blocking during braking. nothing else.

You could simply have a leak in the vacuum servo - or its one-way valve.

I agree that most common ABS problem is one (or more) wheel sensors disrupted. Its such a common problem.

dvhttn · Post by **dvhttn** » 12 Oct 2005, 22:08

Da&n garages! Can't they bleed brakes!?? Got the car back and it had the expected spngy pedal. Bled the rears and all was fine.... 50 squid for nowt on a master cylinder ......