Significant Brake problem

[Mattygreg05]

Hi all,

I’ll try to be brief.
I replaced my brake discs and pads yesterday all round on a Mk4 GT tdi golf non PD 1.9. 1999/2000 T Reg.
Nothing really hard but I did make sure to remove the brake fluid reservoir cap so so no I didn’t hit any issues when rewinding calliper pistons back. Also adjusted my handbrake adjuster to max because not sopping wheels from turning. Despite doing so wheels still move easily with handbrake on.
Anyway. I called it a day, cap back on, wheels back on and brake pedal goes to floor with ease. Pumped it a little and it hardened up slightly before going to floor again.
Went round the block and no brakes. Warning STOP light came on (which is interesting when you actually don’t have any brakes to stop) brake fluid warning. Handbrake symbol flashing on dash too.
Got it home and parked up.
Slight leak noticed on offside rear brake line.
Fluid didn’t move during windback of pistons but after pumping brake pedal went don’t a lot.
Topped up and repeated but had the same result when pumping pedal which still goes to the floor with ease.
I suspect there may be a leak on the rear brake hoses so looking to replace them in the next couple of days. Also will replace the two rear handbrake cables, but anywhere else I ought to be looking or anything else I should have done or not done when replacing the pads and discs?
Typical that the removed discs and pads were actually really good and now wishing I hadn’t changed them in hindsight.
Need some help please guys. Never changed brake hose or handbrake cables before either so could do with advice of doing this also please. ��

[Crasher]

Winding the handbrake adjusters to maximum is an alarm bell, you should not need to do this and immediately says your rear calipers have failed, the simple point is that the cable levers must move back to the rest point without issue. DO NOT whatever you do clamp the caliper flexi hoses to prevent fluid loss, clamp the axle to body hoses. If you let air into the system as it sounds like you have, the system must be pressure bled using a barke fluid pump at no more than 1 Bar also using a diagnostic computer to perform the basic settings which with your Mk20 ABS system is a painful 17 step procedure where you must have a battery charger attached to the car as the procedure drains huge current and even then, if you don’t know the tricks and techniques of bleeding the Mk20 system, you will start doing things like replacing the master cylinder which will dig you an even deeper hole.

[Mattygreg05]

Winding the handbrake adjusters to maximum is an alarm bell, you should not need to do this and immediately says your rear calipers have failed, the simple point is that the cable levers must move back to the rest point without issue. DO NOT whatever you do clamp the caliper flexi hoses to prevent fluid loss, clamp the axle to body hoses. If you let air into the system as it sounds like you have, the system must be pressure bled using a barke fluid pump at no more than 1 Bar also using a diagnostic computer to perform the basic settings which with your Mk20 ABS system is a painful 17 step procedure where you must have a battery charger attached to the car as the procedure drains huge current and even then, if you don’t know the tricks and techniques of bleeding the Mk20 system, you will start doing things like replacing the master cylinder which will dig you an even deeper hole.

Well thank you for the info Crasher, that’s actually scared the buggery out of me now.
You think the rear callipers have failed? What are the identifying issues associated with this diagnosis please?
I can’t understand why that would also prevent my front brakes from working. ?
Why shouldn’t the calliper hoses be clamped please?
Also in the scenario where I may not have introduced air into the system, let’s just say I haven’t done for instance, then I hat procedure would I need to follow to get the brakes working again please?

[Crasher]

Rear calliper failure on the Golf 4 is and always has been a HUGE issue, I have seen brake fluid reservoirs slowly drained by a leaking corroded hose union but also the level warning float stick and not warn of impending lack of retardation... a perfect storm of trouser soiling.

Does the handbrake lever on the calliper return to their stops unaided?

You can let air into the system quite inadvertently such as pushing back an air loaded calliper and blasting air into the system.

You should not clamp the calliper flexi hoses as under the black plastic covering, they are braided Teflon and they crush.

[Mattygreg05]

Rear calliper failure on the Golf 4 is and always has been a HUGE issue, I have seen brake fluid reservoirs slowly drained by a leaking corroded hose union but also the level warning float stick and not warn of impending lack of retardation... a perfect storm of trouser soiling.

Does the handbrake lever on the calliper return to their stops unaided?

You can let air into the system quite inadvertently such as pushing back an air loaded calliper and blasting air into the system.

You should not clamp the calliper flexi hoses as under the black plastic covering, they are braided Teflon and they crush.

thanks bud.
Had it on axle stands again today. I released the tension on the handbrake and they both returned to their stops unaided.
ive readjusted it so they have the slightest gap from the stop. The handbrake now seems to work.

Although I had planned to, ive not replaced the handbrake cables and haven’t replaced the rear brake lines either. Looks like a hideous job.
Think it going to need to go the garage instead to have them replaced.
level of fluid seems ok but there is a leak from the calliper hose to metal hose Union and again slightly on a corroded bend just further along. It squirts out when the brake pedal is depressed.

[Crasher]

Those hoses have been a pain since the early noughties. The corcet way to deal with this is to replace the hoses as the banjo bolts and seals are not officially available, many companies offer these hoses equivalent to VAG numbers 1J0 614 749 left and 750 right. Considering these are only £13.57 each from a VW dealer, it is not worth messing around and they are easy to fit BUT... when you remove the bajo from the caliper you must inspect the aluminum sealing washer sealing face on the caliper, this can become so damaged by electrolysis corrosion that the caliper becomes useless, in VAG's opinion these calipers are not rebuildable and I agree, I will only use new outright (not exchange) TRW units.

Leaking caliper



Corroded washer



Clean and serviceable seating face



New washer on new hose assembly



Fitted and torqued to 38Nm

[Thomaspeed]

Hello I am having exactly the same problem, what was the final solution to the problem?

[Crasher]

Replace the washers with copper ones