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VR6 brakes, rear lockup ?

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What Bias valve?

Hey guys,

My newly built Golf mk1 R32 with Complete VR6 brakes lock-up the rear brakes when braking hard, I fitted this used bias valves, one for each wheel on the rear, but thios doesn't seems to sort out my problem.

My simple questions is, should these valve do the job, and could they be broken inside, leaking? Are thety adjustable, maybe they need to decrease the pressure even more?

Or is these valve no good for the job and in that case, what then ? I google some different adjustable bias valves (Willwood etc.) but I would like to go with OE parts, if it possible?


What do you do when you change to disc brake in the rear of a golf mk1.

Thanks BIAS.jpg

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technically should be using scirocco 16v ones, and even then may not be man enough for mk3 brakes as they have bigger pistons than the scirocco ones do. saying that though, loads have used these type valves with no issues.

one thing, did you remove the residual pressure valves? they're fitted inline with the brake pipes to the rear of the car lower down near the bottom of the bulkhead. those asre only for rear drums and need removing for disc upgrade

Hello my name is John and I'm a dub addict.



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Thanks for the reply rubjohnny.

I did a complete change off all the brake lines, so there is no residual valves mounted.

I pulled the two valves apart and they wasn't really nice inside, so I cleaned them and will fit new O-rings and see if that maybe help, but i doubt it since the lock-up came pretty fast.

So I will need to mount a bias that is adjustable i guess.

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on my cab I made a flat steel bracket then used a mk2 bias valve, with mk1 spring and spring bracket. does mean redoing rear lines though

Hello my name is John and I'm a dub addict.



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Rubjonny: Is it possible to get a picture of that setup ?

I just installed adjustable bias from Wilwood but it not quite enough…  :(

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I think its possible the weight of the engine is making this worse,  weight transfer under braking and all that…

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I Have 620kg on the front wheels and 300kg on the back  .

Does anyone have the axelload on a regular 4 door GTI ?

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But that front weight is actually ahead of the front axle line not on it, so its like a seesaw , and under braking that rear weight is a lot less than static weight..

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I fully agree with you, but it could be fun to compare actual axelload, R32 vs. original GTI ?

I will try with a bias from a golf 2 and see if I can fit it somewhere..

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Would be interesting to see the actual static axle loads with the various conversions versus standard.. I have seen photos of rubjonnys mk2 valve conversion so they do exist somewhere if the photo bucket saga hasnt got them deleted..

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in here :)
https://vwgolfmk1.org.uk/forum/index.php?page=topicview&type=misc&id=your-mk1-golfs_2%2Fproject-83-mk1-cabby

its really easy, a bent kinda J shape bit of steel with 4x holes in.  Not sure if it can close off the rear supply any more than the wilwood though?


Hello my name is John and I'm a dub addict.



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Thank you! I found the pictures.. It looks like it is mounted, where i put my fuel filter.

And the bracked on the reak beam ? Is that and original part, or how is that done ? I dont have anything on my beam that the spring will fit on to…

I think the Willwood will reduce with 57%.

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its on the left side of the car just in front of the rear beam, same place the factory mk1 one is, using the factory mk1 bias valve mountings :)

if you never had the valve first check the mounts are there as they are sometimes not, plus you'll need a mk1 spring and spring bracket plus mounting hardware.

I had everything I needed as mine had the valve, but it was siezed up and new ones were far too expensive. So I decided to try and use the brand new mk2 golf one I had sat on the shelf

Hello my name is John and I'm a dub addict.



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