VW Golf Mk2 Owners Club

Apply pressure to brake pedal = no fluid loss when undoing brake connections?

March 22, 2021, 10:39:05 AM

Hi,

I saw this on the mk2 channel video the other day - think it was you monkey doing the rear axle on the 3.2 Golf.

How does this work? I had expected brake fluid to squirt everywhere from the brake connections by applying pressure on the brake pedal. I can't have the operation of the braking system right in my head.

Are there any time limits on how long you could do this for? I've got a couple of jobs to do that might take me a while (say a week or 2)

1 is to repair this gift which i think will require the brake pipe removing. Mad as it's pretty new and both the copper pipe and flexi was fitted by a reputable garage a year or so ago but no mention of the fault. It must have had an issue as the gromet was never fitted. Side note - want a job doing properly, do it yourself



The other thing i want to do is strip off the front calipers for a refurb.

This is on a corrado rather than the mk2. Corrado brakes can be a pain to bleed so this technique could be be great.

Cheers
Matt

Re: Apply pressure to brake pedal = no fluid loss when undoing brake connections?

Reply #1 – March 22, 2021, 12:28:59 PM

Yeah, it was something I'd bought on a whim, turns out it worked really well.

I believe the brake pedal being pushed pushes the piston past the point where the cylinder can pull the fluid from the reservoir and therefore creating an airlock.
As long as your master cylinder is ok, you shouldn't have a problem with it.
I had mine down for about 30 hours and it didn't loose a drop.

If you're going to bleed the system, the small pressure bleeders are brilliant, takes all the pain out of it.

Re: Apply pressure to brake pedal = no fluid loss when undoing brake connections?

Reply #2 – March 22, 2021, 12:58:11 PM

Cheers. This is the first time I am going to be messing with brakes in this sense (brake pads/discs/sliders etc aside). I do have a sealey pressure bleeder (never used) if all else fails but have a lot to do on this car and trying to keep it as simple as possible.

A related novice quesiton - if i disconnect a caliper (or this flexi) - when i bleed do i just need to do this corner rather than the whole system? I'm trying to avoid that aswell as the fluid is pretty new (< 750 miles on it).

Re: Apply pressure to brake pedal = no fluid loss when undoing brake connections?

Reply #3 – March 22, 2021, 02:08:26 PM

If you manage to get the brake pedal thing to work and no more fluid comes out, you should be good just bleeding that one corner.
Also, sometimes, if you have problems bleeding the rear, try jacking up the rear beam, so it simulates the rear of the car being loaded up. That helps get the fluid down to the rear.

Re: Apply pressure to brake pedal = no fluid loss when undoing brake connections?

Reply #4 – March 22, 2021, 05:22:29 PM

Thanks.

Just looking to collect some bits for futurejobs and perhaps this one - thinking about making a blanking cap - what diameter are VW brake lines is it 3/16? 

Re: Apply pressure to brake pedal = no fluid loss when undoing brake connections?

Reply #5 – March 23, 2021, 01:24:31 PM

My top tip would be zip tying the rear compensator. Before I did this I just couldn't do the rear brakes. Jacked the car up and still no joy. I used a Gunson kit I think - from Screwfix for about £20. I'm sure there's better/cheaper ones out there, but once I had let some air out of the spare tyre (it needs a low PSI to work) the system worked well. A little more fiddly than I'd hoped but used minimal fluid (I'd changed my M/C and all the solid brake lines) so needed a full flush/replace) and was pleased to have done it all myself!

Re: Apply pressure to brake pedal = no fluid loss when undoing brake connections?

Reply #6 – March 23, 2021, 02:24:46 PM

I've ordered a female blank but want to crack on really. If i disconnect it, with the pedal technique, will this line just drip constantly? I don't have an old flexi i can mole grip.

I have some many tools but never what I need.

This issue is up in the front arch but will defo use your tip when I need to do a full bleed. Trying to avoid it on this car if i can as the fluid was only changed 750 miles ago plus have a lot of jobs to do and want it back on the road by early summer

Re: Apply pressure to brake pedal = no fluid loss when undoing brake connections?

Reply #7 – March 23, 2021, 03:14:51 PM

When I done the rear beam, I only had the pedal held down with that thing.
Didn't lose more than a drop or two, didn't even bother with a blank.

Re: Apply pressure to brake pedal = no fluid loss when undoing brake connections?

Reply #8 – March 29, 2021, 09:36:37 PM

This technique worked a treat tonight. Zero fluid loss! I just used a spirit level to wedge in to press the brake pedal. I have capped off for now. Great tip