Residual Pressure - after Brake Proportioning Valve

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Originally Posted by davep

So what was Tilton's revelation on how their proportioning device creates a lock-up. Essentially that is a total failure of their device to do what is promised.

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So this is their answer
Hello Uli,

Sorry this took so long but it took a while for me to replicate the problem on the test rig. When I introduce some air into the system, I can make the valve respond similarly to what you have seen in your car. I think the problem is with the volume of fluid trying to flow through the valve. I also noticed in your video that the brake pedal is taking a very large amount of travel to actuate (indicating either air in the system or the drum brake shoes being out of adjustment). So it seems like in this condition, with a large increase in fluid displacement through the valve, that it is able to get stuck in position.

I would be interested to see what happens in your car when the shoes are properly adjusted and the system is bled thoroughly.

Regards,

and my reply

Hello Jason,
when I remove the pressure gauge I have a firm pedal, but the problem persists.
I have a bleeding thing that puts pressure on the fluid container and has vacuum at the bleeder valves. I’ve even bled the system with the rear jacked up to make sure the valve in the tunnel isn’t the highest spot. I’ve tried both with the shoes adjusted for minimal clearance and with reset adjusters, but it makes no difference.
Out of curiosity I tried blowing through the valve from the “out” connection. Wasn’t possible with a bit of preload on the adjuster.
Any more ideas?

Thanks Uli

I have the exact same problem with the Tilton proportion valve When mounted on my 914/6. Bought the valve the end of 2021.

Jonas

I had sent back the tilton valves and got my money back. The ap racing valve I now have is on a totally other level of appearance and quality and works like it is supposed to.

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Originally Posted by uai

I had sent back the tilton valves and got my money back. The ap racing valve I now have is on a totally other level of appearance and quality and works like it is supposed to.

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Is it AP screw type you use Now?

Yes, this one- required a larger hole and the threads of the tube need to be longer but it really works well.
https://www.isa-racing.com/fahrzeugt...rehknopf?c=465

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Originally Posted by uai

Yes, this one- required a larger hole and the threads of the tube need to be longer but it really works well.
https://www.isa-racing.com/fahrzeugt...rehknopf?c=465

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Thanks!
Grind off a bit of material of the threads on the ventile must work also?

Well I wouln't do that - just spend the 2 euros and use the long ones
Attachment 567100

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Originally Posted by uai

Well I wouln't do that - just spend the 2 euros and use the long ones
Attachment 567100

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On my 914/6 its really tight place and hard to get the Oil pipes out to modify them.

Then I'd choose another Manufacturer, I think wilwood only has NPT thread but there should be others on the market

I assume you have a condition with too much rear brake, as no proportioning valve can add rear brake pressure.