Adjustable Proportioning Valve

[caveeagle]

Man you guys must be running octagonal tires with all the locking up you are doing.

But seriously, how do you avoid flat-spotting a good set of tires when making your trial brake skids?

[Renegade600]

Do't think I've never flat spotted a tire setting bias.... just brake quick and adjust... you quickly will get the feel of where it needs to be... set the valve and leave it....unless you are doing burnouts...

[caveeagle]

The best way to set the brake bias is with a gauge on the front and back.
It's a bit of work, but a lot of piece of mind.
1200 psi on the front and 800 psi on the rear should work great for you.
You want the front about 15 to 20 precent more than the rear.
This is a great kit, but you need two kits to do it correctly.

I was thinking about this over the weekend. It seems that setting the brake bias using only pressure could get you into trouble (potentially). Different brake systems will have a different braking force at a given pressure. Right? Even just changing the type of brake pad/shoe can have an impact on braking efficiency.

I like the idea of using the pressure guages, but think a reality check is in order.

[4mustangs]

Originally Posted by caveeagle

I was thinking about this over the weekend. It seems that setting the brake bias using only pressure could get you into trouble (potentially). Different brake systems will have a different braking force at a given pressure. Right? Even just changing the type of brake pad/shoe can have an impact on braking efficiency.

I like the idea of using the pressure guages, but think a reality check is in order.

If your brake system is original, Part 2-2 of the shop manual says:

PROPORTIONING VALVE

The proportioning valve is serviced
as an assembly and is never
adjusted or overhauled

[caveeagle]

Originally Posted by 4mustangs

If your brake system is original, Part 2-2 of the shop manual says:

PROPORTIONING VALVE

The proportioning valve is serviced
as an assembly and is never
adjusted or overhauled

4m, I don't thing anyone on this thread is talking about a stock/original brake system. I am not aware of any mustangs that came stock with an adjutable prop valve.

And as a side note, I have found several occasions when the factory shop manual is defficeint or incorrect. ie: According to factory shop manual trouble shooting guide, the stock guage cluster on my 04 cobra is not servicable and should have been replaced at a cost of ~$400. I found an aftermarket supplier for the indiglow inverter if fixed it myself for $20. I know that brake systems are different, but that shop manual comment would not be a show stopper for me.

[ScotiaFE]

Originally Posted by caveeagle

I was thinking about this over the weekend. It seems that setting the brake bias using only pressure could get you into trouble (potentially). Different brake systems will have a different braking force at a given pressure. Right? Even just changing the type of brake pad/shoe can have an impact on braking efficiency.

I like the idea of using the pressure guages, but think a reality check is in order.

This is exactly how Stainless Steel Brake Corporation wants you to set the bias.
Which I run on my really fast Fords.
Actually most brake systems operate at around these pressures.
Sliding your car on gravel sounds really technical. Which size of gravel do you use?

[stephanorf]

Originally Posted by 4mustangs

If your brake system is original, Part 2-2 of the shop manual says:

PROPORTIONING VALVE

The proportioning valve is serviced
as an assembly and is never
adjusted or overhauled

I read that note about the proportioning valve being serviced as a unit. Unfortunately, Ford never intended for the proportioning valve to be rebuilt. But they now sell rebuild kits for the stock valves. I have rebuilt the proportioning valve on my 65 but it is not running yet. I assume I will have to make adjustments on the rebuilt valve to get the front-to-back braking proportioned correctly.

Does anyone have experience with rebuilt factory proportioning valves? Any hints on making adjustments that might be different then on the aftermarket proportioning valves?

Before


After


I counted the number for threads and put it back together as close to the factory setting as possible.


Has anyone rebuilt their original proportioning valve? If so, did you reassemble the unit as close to the factory setting as possible, and then did you still need to make adjustments?

Thanks!

[4mustangs]

Originally Posted by caveeagle

4m, I don't thing anyone on this thread is talking about a stock/original brake system. Really, how do you know that? The OP didn't say.
I am not aware of any mustangs that came stock with an adjutable prop valve. Adjustable or not that does not prevent someone without the proper knowledge and skills from screwing it up because he misread a thread here. We have people asking how to adjust things when they don't understand what they do. I posted this because I think we need to be clear about what we are talking about here.

And as a side note, I have found several occasions when the factory shop manual is defficeint or incorrect. ie: According to factory shop manual trouble shooting guide, the stock guage cluster on my 04 cobra is not servicable and should have been replaced at a cost of ~$400. I found an aftermarket supplier for the indiglow inverter if fixed it myself for $20. I know that brake systems are different, but that shop manual comment would not be a show stopper for me.

Yes brake systems are different, they can kill you. I have lived long enough to experience a partial to total brake failure on 3 different cars. The post was not meant to stop you, just to suggest caution.

[22GT]

Originally Posted by caveeagle

Man you guys must be running octagonal tires with all the locking up you are doing.

But seriously, how do you avoid flat-spotting a good set of tires when making your trial brake skids?

Gravel roads.

[22GT]

Originally Posted by stephanorf

I read that note about the proportioning valve being serviced as a unit. Unfortunately, Ford never intended for the proportioning valve to be rebuilt. But they now sell rebuild kits for the stock valves. I have rebuilt the proportioning valve on my 65 but it is not running yet. I assume I will have to make adjustments on the rebuilt valve to get the front-to-back braking proportioned correctly.

Does anyone have experience with rebuilt factory proportioning valves? Any hints on making adjustments that might be different then on the aftermarket proportioning valves?

I counted the number for threads and put it back together as close to the factory setting as possible.

Has anyone rebuilt their original proportioning valve? If so, did you reassemble the unit as close to the factory setting as possible, and then did you still need to make adjustments?

Thanks!

Ford's intentions had nothing to do with it. They bought them from Kelsey Hays. They weren't interested in selling anything but the whole piece. This is pretty normal, many things came as assemblies only.

Adjusting the function is the same as aftermarket valves.

You painted it the wrong color. When new, they were non-metallic light gray, with a dab of yellow paint on the side.

[geicoman58]

oh great googily moogily---time for a snickers bar

[stephanorf]

Darn it! haha..no biggie, I'll just repaint it grey. I have all the brake lines connected, but no brake fluid in them yet. Is the master cylinder the same color or bare cast iron?

[supershifter2]

Originally Posted by geicoman58

oh great googily moogily---time for a snickers bar

i'll take a kit-kat bar !