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Username Post: Where are you mounting proportion valve?        (Topic#355044)
Gguerra 60
Silver Supporting Member
Posts: 23
Gguerra
Age: 60
Loc: NH
Reg: 01-20-19
01-31-19 05:28 PM - Post#2758700    

So....
As I move through this project,I have come up against a quandary.......
I mounted my new booster and master cylinder to the firewall of my 51 SD.....as I have installed discs for the front, I picked up a GM style proportioning valve.
My question is.... where to put it?
Close to the mc will be kind of spaghetti looking.
Any better spots?
On the frame below alternator?
On inner fender near alternator?


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Shepherd 
Frequent Contributor
Posts: 1789

Loc: Lake George, NY
Reg: 11-11-15
01-31-19 05:47 PM - Post#2758703    
    In response to Gguerra

That's pretty much the standard mounting location.



 
Gguerra 60
Silver Supporting Member
Posts: 23
Gguerra
Age: 60
Loc: NH
Reg: 01-20-19
02-01-19 04:26 AM - Post#2758726    
    In response to Shepherd

Which one?



 
Shepherd 
Frequent Contributor
Posts: 1789

Loc: Lake George, NY
Reg: 11-11-15
02-01-19 08:51 AM - Post#2758745    
    In response to Gguerra

Sorry, bracket on the master/ booster.



 
Bel Air kiwi 
Deceased Member RIP
Posts: 4558
Bel Air kiwi
Loc: New Zealand
Reg: 04-24-14
04-15-19 01:54 AM - Post#2764244    
    In response to Shepherd

Hi Guy, that is actually a combination valve that normally includes a fixed value proportioning valve. A metering valve, and a pressure warning switch.

I don't like them in the hobby car field because they are only the right values if you have the complete brake system from the donor vehicle and it was of the same weight and bias of your current vehicle.

In the OE market they had a specific function which allowed cars from the same family to have either drum or disc fronts without changing the rear ends.

They were part numbered and very specifically matched to the vehicles options/specs. Unfortunately, the same exterior housing was used for multiple applications and was often set to work the other way around. What is in an aftermarket version is anyone's guess.

Unless you pipe the master to that valve incorrectly they will sort of work ok but they are usually a long way off optimum.

But personally, I mount them in the rubbish bin.

All disc systems don't use them and neither do all drum systems.

What they are fudging over is the fact that drum brakes can rarely tolerate a boost ratio above 1.3:1 and disc brakes are usually needing a boost ratio in the order of 2.0:1 and higher.
As well as being capable of far more stopping power disc brakes act more quickly than drums, particularly if the drums don't have RLP valves.
So part of that valves job is to hold off (delay the discs working.) and this is done through a fixed value pressure valve.


If you want me to help you further on this you will need to give me the spec's on the master and booster as well as what is going on at each wheel.

This area has been covered in past posts so you may wish to look them up.

Cheers Kiwi







48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars.

"They made a desert and called it peace." Tacitus


 




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