Author Topic: MK1 soft brakes  (Read 1676 times)

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MK1 soft brakes
« on: Jun 21, 18, 19:02 »
I've been fighting an issue on my 83 GTi with the brakes.
At one point they worked fine..but can't seem to figure out how to get a firm pedal when the car is running.
It has a 2.0L aha motor swap
Ive replaced the master cylinder, the brake booster and its check valve and blead the brakes. There is no leaks from what I can see.
The brakes have pressure when I have the ignition off and are firm but once I start the car, they go spongy and the pedal isn't firm, there is still some pedal, it doesn't go to the floor but its soft. Any one have this happen to them? Looking for some advice on what I should trouble shoot next
I have a check valve that I purchased but don't know where it goes or where I need it?
Any guidance or advise would be greatly appreciated.
Thank you Dubberz

Benyameen Kawlboose

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Re: MK1 soft brakes
« Reply #1 on: Jun 22, 18, 11:48 »
You sure the check valve is in the right way?

Usually an issue like that is due to a vacuum leak somewhere. I would check over everything again

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Re: MK1 soft brakes
« Reply #2 on: Jun 22, 18, 12:17 »
A bad brake booster would make your brakes firmer, not softer. This isn’t a booster or vacuum issue. It’s a hydraulic issue. Do you properly bench bleed the master cylinder before installing in the car? Bled all four corners properly and in the correct order; several times? Lots of fluid came out each corner? Drums are properly adjusted and you have lots of meat on the front pads?

Bleed the brakes again.
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Re: MK1 soft brakes
« Reply #3 on: Jun 22, 18, 16:47 »
How old are the soft lines??... could be the reason... try new lines or braided
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Re: MK1 soft brakes
« Reply #4 on: Jun 22, 18, 18:30 »
I second the rear drum brake adjustment issue. If they are out of adjustment it will give you a soft pedal due to the longer throw.
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