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Brake proportioning valve

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nwguy

Number of posts : 43
Location : Poulsbo, WA
Registration date : 2017-04-16

Brake proportioning valve

Post by nwguy on Sun Oct 22, 2017 4:33 pm

I recently finished installing my D&D front disc brake conversion kit. I got the deluxe one with the master cylinder and remote reservoir. The brakes lock up every time I braked in a parking lot. I thought it was the front ones locking up, but now I'm thinking it must've been the rear. Need to have someone else observe while I'm testing. The prior owner has a Willwood brake proportioning valve installed, and it's used on the FRONT brakes. I read the installation manual:

http://www.jegs.com/InstallationInstructions/900/950/950-260-8419.pdf

It says to install it for the rears, not the front. Seems like I should change it. Yes???
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Seth G
Vintage-Vans Listings Manager
Vintage-Vans Listings Manager

Number of posts : 1720
Location : Anacortes, WA
Age : 44
Registration date : 2013-04-24

Re: Brake proportioning valve

Post by Seth G on Sun Oct 22, 2017 5:11 pm

Yes, the prop valve should be adjusting the rears. The fronts probably aren't going to lock easily. I don't know what's in that master cylinder, they may be in there, but you should have a 2# residual valve on the front line and a 10# on the rear. If they aren't there, or there is just one on the rear port, you should add one on the front line or both if there is none in the master. Once you get the prop valve moved to the rear line you want to do a series of hard stops, in a safe area, adjusting the valve until it won't lock up in the rear. Could be life and death in a hard stop situation and the last thing you want is the rear end to come out from behind you and steer you God knows where.

Old Skool
Econoline Guru

Number of posts : 1219
Location : North Hills, CA
Age : 65
Registration date : 2009-06-13

Re: Brake proportioning valve

Post by Old Skool on Mon Oct 30, 2017 8:59 am

I thought this thread had been well discussed many years ago?? 
   DRUM BRAKES are MECHANICAL POWER BRAKES by operation!!!!!!  This not a new reply again... LOL
 Caliper pistons are ONLY operated by pressure applied TO THEM with no mechanical multiplication other than the actual pressure applied to the piston, regardless of power brakes or non power brakes. Power brakes systems typically with a LARGER piston size to slow them down a touch and not be so violent in operation HOWEVER the caliper piston still ONLY affected by line pressure alone.

 THAT IS THE REASON of why the rear drum brakes CAN lock up BEFORE the disc brake will and the reason of WHY the flow to the drum brake circuit NEEDS to be slowed down. This IS CALLED BRAKE BIAS which also includes front and rear weights, tire sizes,, etc,etc...  AGAIN explained in detail in the book "HOW TO MAKE YOUR CAR HANDLE" by Fred Puhn, (HPBOOKS--46)
 The stock drum brake Econoline BRAKE BIAS controlled by different sized wheel cylinders in the back versus the rears. 
 Also stated sooooooooooo many times. A 10 lb valve CAN LOCK UP A DISC BRAKE CALIPER as it HAS NO RETURN SPRINGS as drum brakes do. 
  A 2 lb RESIDUAL VALVE (check valve) IS RECOMMENDED for a disc brake circuit in which the calipers or brake lines are ABOVE the master cylinder reservoir height as it can  cause a drain back to the M/C. Believe it or not stated in numerous tech articles.
 A proportioning valve does exactly as it says, it PROPORTIONS the brake fluid. So,, if a drum brake is a mechanical power brake by operation wouldn't it also make sense also that it can lock up before a disc brake caliper can lock up!!!  and the reason of why its operation needs to be slowed down to match the front disc brake caliper. THUS A PROPORTIONING VALVE IS NEEDED. Whoever stated that it needs to slow down the disc brake and not the drum brake is WAY OFF BASE regardless of who is saying that!!!
  SOME also saying to use a PRE SET proportioning valve of which CAN ONLY BE CLOSE to the vehicles particular BRAKE BIAS and would be LUCKY to properly adjust the BRAKE BIAS if AT ALL and the reason of why I ONLY use an ADJUSTABLE proportioning valve on my disc setups.
OLKSKOOL

Old Skool
Econoline Guru

Number of posts : 1219
Location : North Hills, CA
Age : 65
Registration date : 2009-06-13

Re: Brake proportioning valve

Post by Old Skool on Mon Oct 30, 2017 9:06 am

Tried to send images but but it wont access?  anyone know of why??
msg,,,, ERROR  "cannot obtain dp informations 2"
  ALSO, just read the installation instructions and it specifically says "normally installed in the REAR LINES,,, lol
OLDSKOOL
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Casimier

Number of posts : 858
Location : Jackson,NJ
Age : 64
Registration date : 2010-07-26

Re: Brake proportioning valve

Post by Casimier on Sat Nov 04, 2017 7:04 am

Thanks Vic
On something so important

Old Skool
Econoline Guru

Number of posts : 1219
Location : North Hills, CA
Age : 65
Registration date : 2009-06-13

Re: Brake proportioning valve

Post by Old Skool on Sun Nov 12, 2017 8:40 am

Pictures are working now??????????  Posted before but again to try and help.  I mount it under the seat and out of the way but VERY easy to use. You dont have to stop the truck and get out, go under the truck and adjust it, or anything else. You can adjust it while you are driving and is super easy to adjust. You dont know its there unless you put your hand on it. In my 1st attempts I used rubber grommets for the lines to go through the floor but found it hard to thread the bent lines through them very cleanly.
 SO,,, why not use a bulkhead fitting,, (duh),,, SOLID mounting point, no issues with grommets or leaks or anything,, as always,, I try to use stainless when I can..
OLDSKOOL


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nwguy

Number of posts : 43
Location : Poulsbo, WA
Registration date : 2017-04-16

Proportioning valve installation

Post by nwguy on Sun Nov 12, 2017 9:27 am

That's a nice clean installation of your proportioning valve Vic. Great location. Mine's at the very front of the bottom of my doghouse. Can easily reach it from the driver's seat, but you have to lift the doghouse.

Old Skool
Econoline Guru

Number of posts : 1219
Location : North Hills, CA
Age : 65
Registration date : 2009-06-13

Re: Brake proportioning valve

Post by Old Skool on Tue Nov 14, 2017 7:57 pm

I did one other for a customer inside the doghouse just in front of the radiator and was much easier to plumb up, but I like this one the best as you dont have to reach for it or hold the lid open,, way too easy to operate and you cant see it

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