Mark 4 Golf Brake Bleed Issue

GTE

Howdy,

I changed a rear brake calliper today. I clamped the flexible pipe as per the Haynes and everything went smoothly. I bled the new caliper till there was no air in the Draper one man bleeder hose. I kept an eye on the fluid level and topped up in between each brake pedal depression.

The brake pedal now goes to the floor with very poor performance. This has happened once before when a mechanic did the brakes for me (all round pad and disc replacement + fluid renewal).

These cars seem to be a pig to do brake work on judging by google but there is no mention of any special considerations to make in the Haynes manual.

Any advice? I read that the ABS and master cylinder bleeding are things to focus on.

Thanks!

Interslice

Might want to try bleeding all calipers starting with the furthest from the master cylinder.

I found that with the one man kit aren't great with just one man. Air was sometimes sucked back into the caliper from the threads on the bleed nipple. The best way I think to do it is to get someone else to press the pedal.

• - put pressure on the pedal
• - open the bleeder
• - when the pedal hits the floor close the bleeder
• - release the pedal

Haven't had any problems doing it this way. The bleeder is always being opened and closed under pressure just like with a pressure bleeder.

GTE

Thanks for the reply. Just back from a session under the wagon.

I think you are spot on with the one man kit thing. Suppose 6 quid is too good to be true.

After some bleeding as per instructions I decided to close the nipple, dab the brakes till they were hard and then loosen the nipple. It looked like the pressure then pushed the fluid out. I did that a couple of times. I didn't see any air but i was moving around so could have missed it.

When I finished I got a much more positive response with the engine off (rock hard). When driving I got the ABS going on a hard stop. I did notice that my foot would eventually go close to the floor over 10 seconds when stopped but there was always pressure against my foot. Is that normal?

Seems odd to me that I could have foot to the floor from one corner having a bit of air in.

bbsrs

bbk wrote: »

Thanks for the reply. Just back from a session under the wagon.

I think you are spot on with the one man kit thing. Suppose 6 quid is too good to be true.

After some bleeding as per instructions I decided to close the nipple, dab the brakes till they were hard and then loosen the nipple. It looked like the pressure then pushed the fluid out. I did that a couple of times. I didn't see any air but i was moving around so could have missed it.

When I finished I got a much more positive response with the engine off (rock hard). When driving I got the ABS going on a hard stop. I did notice that my foot would eventually go close to the floor over 10 seconds when stopped but there was always pressure against my foot. Is that normal?

Seems odd to me that I could have foot to the floor from one corner having a bit of air in.

Any luck figuring this out my pedal goes to floor too over about 10 seconds?

CJhaughey

Is it diesel?
If so its known as diesel creep, and pretty much normal.
If its petrol then its a problem.

bbsrs

CJhaughey wrote: »

Is it diesel?
If so its known as diesel creep, and pretty much normal.
If its petrol then its a problem.

It's diesel but even with the creep it doesn't stop as good as my other tdi golf . Thanks for the reply.

CJhaughey

bbsrs wrote: »

It's diesel but even with the creep it doesn't stop as good as my other tdi golf . Thanks for the reply.

That could be due to many factors, Brake pad compound, Brake disc steel. etc etc.

Stoolbend

Is there 2 bleeders on the master cylinder in the mk4? Try bleeding them.

GTE

There are some great videos on the Toob.

https://www.youtube.com/results?search_query=mark+4+tdi+master+cylinder

Chimaera

bbsrs wrote: »

Any luck figuring this out my pedal goes to floor too over about 10 seconds?

Check the vacuum lines: they corrode and leak over time. As well as screwing up turbo operation, the vacuum system also runs the brake servo. A 2003 model with the original lines is likely to be leaking by now.

GTE

bbsrs wrote: »

Any luck figuring this out my pedal goes to floor too over about 10 seconds?

I havent checked it since. I went through the NCT with the braking passing with no issue. My fluid is old, which I am renewing on Monday.

Never heard of diesel creep, but it sounds like that could be it now that I have done some reading up. I have no reference point of another Golf TDI, but I have not had any stopping issues.

There is a 2004 Corolla hatchback which stops a lot quicker than my Golf estate, but there is about 100ish kg difference between the two with mine being heavier.

corkgsxr

Iv had fierce problems with cheap brake fluid. Acts like there's air in the system but there's not.

Castrol is all I use now.

Halfords fluid is particularly bad.


Get the other type bleeder. You fill a container and connect to reservoir. And pressurise off tire. You then just go round to each point and draw off fluid.

System is always under pressure so no way to draw in air

whizbang

I was told years ago, to remove, clean, and cover some heavy grease all over the bleed nipple..

There's many bleed nipples rusty inside the caliper, and just don't seal properly unless greased.

GTE

I had the Gunson pressure bleeder for weeks before I actually got around to doing it today.

There is a much more solid feel to the brake pedal, even for the light braking required for reversing out of the drive way.

Though, after doing some brake tests on empty, high quality new road surface I was alarmed at how easily the ABS was kicking in. It was wet and I never really did hard braking in the wet before so I guess it was new territory for me. Coupled with the fact that I had just done the brakes, I was probably not as objective as I should have been. It is amazing how much the wet can feck up your braking distances.

It dried up and it stopped much better than before so solid feel and more confident braking.

The only thing I can liken it to, is that the brakes apply quicker or more suddenly than before. Not to say it is a brake on or off situation, but with the old fluid there was a noticeable fade from no brakes to braking.

I am all for having grease on the bleed screws, one was a complete pain to do.

CJhaughey

whizbang wrote: »

I was told years ago, to remove, clean, and cover some heavy grease all over the bleed nipple..

There's many bleed nipples rusty inside the caliper, and just don't seal properly unless greased.

A less messy way is to use Teflon plumbers tape.
Just a wrap or two will do.

Chimaera

Be careful using any grease around the bleed nipple - if it gets into the brake fluid it may cause unpredictable behaviour. The only difficulties I've ever had with bleed nipples was when the previous owner had lost the rubber caps and they rusted solid. I replaced all the nipples and caps on my car about 6 years ago and they've been perfect ever since.

mphalo1

I assume you have a short bit of clear pipe fitting snug onto the bleed nipple as your bleeding them it stops it sucking back in air as the pipe itself will fill with fluid stopping that from happening??

GTE

mphalo1 wrote: »

I assume you have a short bit of clear pipe fitting snug onto the bleed nipple as your bleeding them it stops it sucking back in air as the pipe itself will fill with fluid stopping that from happening??

That is the norm alright.

With some one man bleed kits, there will be a one way valve built in to the end of the pipe to make things easier.

With the Easy Bleed system, the air pressure from the spare tyre means there can be no air drawn back into the system via the bleed screws.

corkgsxr

CJhaughey wrote: »

A less messy way is to use Teflon plumbers tape.
Just a wrap or two will do.

Iv never needed grease or ptfe and if your putting tape on the threads that's not the sealing face so it's useless.

CJhaughey

corkgsxr wrote: »

Iv never needed grease or ptfe and if your putting tape on the threads that's not the sealing face so it's useless.

You aren't sealing the face of the plug, you are ensuring the threads don't become seized.
If you have never encountered a seized bleed nipple then you haven't worked on many calipers, very common complaint.
Many need heat to unseize.

corkgsxr

CJhaughey wrote: »

You aren't sealing the face of the plug, you are ensuring the threads don't become seized.
If you have never encountered a seized bleed nipple then you haven't worked on many calipers, very common complaint.
Many need heat to unseize.

Iv worked on all ages and maybe Iv been lucky but Iv never got a seized or snapped a nipple