Manual Proportioning valve install

[TDW]

I just ordered a Wilwood knob proportioning valve for my 86 E350 6.9 van. It has a "self adjusting" valve mounted under the van in the rear. I want to figure out how to bypass that valve and add a manual valve with a knob.

http://www.polyperformance.com/show....com/shop/images/D/260-8419-400.jpg&tmbn_alt=

I'd love to mount this inside the van's cabin, but that would require me to run some brake lines into the cabin from the engine compartment. There's not too much room from inside the engine compartment for mounting this.

Has anyone ever tried interior mounting on one of these? What type of parts should i be looking for to make this modification happen? Will it matter if I increase the volume inside the brake line (elongate, or add to)? It seems that if it is a hydrolic line, and there is no air, that adding extra length to the line itself most likely won't matter.

Any thoughts? Anyone out there have amanual valve installed in the interior? Pics?

 

[crashnzuk]

I can't see it being an issue mounted inside the van. To eliminate the height proportioning valve, just get the appropriate flare union, or make a jumper if necessary, to connect the 2 lines that went to the valve.
Travis..

 

[LCAM-01XA]

No issue with adding extra length of brake line. But, may I suggest that you simply drill a hole in your floor, and then run the valve's knob through there? Make some sort of right-angle bracket to attach the valve to the cab floor, then run brake lines to the valve. The rear valve can by bypassed very easy, just run all new brake line from the manual vale directly to the rear axle brake hose - chances are by now you probably need new steel lines anyways.

By the way I had that same manual valve right next to the brake booster in my old Chevy, wasn't adjustable on the fly there, but it worked good regardless.

 

[OLDBULL8]

May I ask why do you need a manual proportioning valve? Are you going to race that Van?

 

[LCAM-01XA]

Factory load valve died, and he wants to still be able to get proper line pressure to the rear whether he's running empty or at full load?

 

[TDW]

May I ask why do you need a manual proportioning valve? Are you going to race that Van?

If I planned on racing the van, I should also plan on not ever winning! I am buying the valve because I thought that it was the most logical thing to do, and it was recommended.

Yes it's true that my main goal is to be able to control the pressure to the rear brakes. As of now, when i first tried bypassing the existing valve (by removing rubber seal inside the cylinder of the valve, which was not intact when I took it apart), I was stopping well. Then the brake light came on, and it takes a lot of leg power to stop the darn thing. I'm thinking that there's still air in the system somewhere, although I've bled it quite a few times using techniques I learned on this forum.

I like the idea of manually controlling the pressure to the rear brakes, but if just bypassing the existing valve, or pulling a used part from the junk yard and replacing it is a better idea, I'd go with that. I don't want to create more work, I just want to stop easily, confidently, and keep all passengers safe.

 

[jperecko]

No issue with adding extra length of brake line. But, may I suggest that you simply drill a hole in your floor, and then run the valve's knob through there? Make some sort of right-angle bracket to attach the valve to the cab floor, then run brake lines to the valve. The rear valve can by bypassed very easy, just run all new brake line from the manual vale directly to the rear axle brake hose - chances are by now you probably need new steel lines anyways.

By the way I had that same manual valve right next to the brake booster in my old Chevy, wasn't adjustable on the fly there, but it worked good regardless.

I would go with this route... I did it for my manual fuel selectors and it worked well. Pick up some rubber grommets from McMaster and you can have a weatherproof seal to the metal floor.

 

[LCAM-01XA]

Then the brake light came on, and it takes a lot of leg power to stop the darn thing. I'm thinking that there's still air in the system somewhere, although I've bled it quite a few times using techniques I learned on this forum.

That may be an unrelated issue, it actually sounds like your vacuum pump is dying on you and you lose brake assist because of that- put a vacuum gauge on the pump line directly and tells us what numbers you see, should be well over 20"Hg at idle.

I like the idea of manually controlling the pressure to the rear brakes, but if just bypassing the existing valve, or pulling a used part from the junk yard and replacing it is a better idea, I'd go with that. I don't want to create more work, I just want to stop easily, confidently, and keep all passengers safe.

Bypassing the load sensing valve without adding another means of dialing down the line pressure is not a good idea because you end up with full line pressure all the time - with that if you floor the brakes when you're empty you're much more likely to lock up the rear wheels and have the van go sideways on you. The more weight you have over the rear axle the more line pressure the rear brakes can receive before they get to the lockup point, and this is what that valve you're bypassing does. I hear it actually works pretty good when it works, I dunno how expensive it is but for the sake of ease of operation of the van (especially by someone who's not tech-savvy
enough to tinker with a manual valve) it may not be a bad idea to just keep the factory setup? Junkyard parts I dunno if I'd trust, as there's no guarantee what you're getting is any better that what you got now, maybe if it's been freshly replaced before the truck got junked then it can be a good score...

Do check your vacuum pump first tho, as hard pedal is most commonly cause by that, and not inop rear brakes.

 

[TDW]

Do check your vacuum pump first tho, as hard pedal is most commonly cause by that, and not inop rear brakes.[/QUOTE]

That makes sense. I'll check it out and will report back.

 

[jim x 3]

X2 re: LCAM's response to brake light issue. In my '88 the most likely cause of a brake warning light is low/no vacuum or low level in the master cylinder reservoir. The brake light may be an artifact of you messing with the rear brake lines.

And X2 re: LCAM's response about replacement rather than bypass/manual valving. If your going to have a broad range of loads in the back - no passengers to chock full - then you want the proportioning to be done automatically in response to rear end load. You don't want to have to mess with that each time your load changes. And if you set it and forget it, then your braking will only be optimal at one loading.

Regards,

 

[LCAM-01XA]

X2 re: LCAM's response to brake light issue. In my '88 the most likely cause of a brake warning light is low/no vacuum or low level in the master cylinder reservoir. The brake light may be an artifact of you messing with the rear brake lines.

That's true, but since he mentioned having to really stand on the brake pedal it suggests to me that he ain't getting the brake assist he needs. case in point - on my old Chev after installed hydroboost the first time I floored the brakes she promptly blew a front brake line, so I replaced the fronts, then when I went for a rerun of the pedal-floor test she blew the rear line - that was enough for me at the time, so I simply capped off the master cylinder port and ran the truck on front brakes only for like a month till I got some time and motivation to run a new rear line. During this time she stopped just fine, maybe not as quick as she did later on with all four brakes working, but the pedal effort was normal and I never had to jump on the pedal to make her stop - actually the one time I did that cause someone pulled out in front of me the truck dove so hard the rear wheels came off the ground, impressed the heck of some kids in a Camaro

And X2 re: LCAM's response about replacement rather than bypass/manual valving. If your going to have a broad range of loads in the back - no passengers to chock full - then you want the proportioning to be done automatically in response to rear end load. You don't want to have to mess with that each time your load changes. And if you set it and forget it, then your braking will only be optimal at one loading.

There is actually another style of manual brake bias valve that instead of a knob you rotate has a small lever with a ball-and-rooster-comb clicker built in that gives you like 5 or 6 fixed settings for the pressure drop - one end is full pressure, other end is 50% off, and the positions between are like 10% pressure drop each. It's like double the price of the regular one with the knob tho, but for sake of ease of operation it may be a better choice for TDW's van.

 

[franklin2]

I would also recommend you mount it down low in the floor. If you get a large upward loop in the brake line, it will not affect your braking but it will be a good place for lots of air to get trapped which would be difficult to remove. Air likes to rise upward in the high spots of the system.

 

[TDW]

Yes it would be great to just use the system the way it was designed, and it would be nice to not have to rely on changing the pressure when dealing with weight variables.

I kind of got the impression that the manual route was better, and that the original valve wasn't worth keeping.

When I removed the valve and finally got air to pass through it, I thought I was set, but after taking the top bolt off which holds a small piston up against a spring (just like in any other hydrolic valve) and found the damaged rubber seal, I figured it would be better to replace or modify. especially when this whole hard braking occurred.

I'll run some more diagnosis on the vacuum, and maybe just replacing the o-ring seal in that valve cylinder will do the trick for proportioning.

Thanks for all the ideas and support!

 

[LCAM-01XA]

Well I've never taken that valve apart, my buddy's truck has it but it's seized and his truck sops good so I chose not to mess with it. I personally have the RABS with electronically-actuated valves so it works in a much different manner than what you have... I'd say if you know what they look like on the inside and how they should operate just rebuild it so it works like it did from the factory.

And still do the vacuum pump test, as they are known to weaken and sometimes fail completely, I've been there with my truck too...

 

[TDW]

I bought a vacuum tester today, and I'm looking forward to getting to the bottom of this hard braking issue. I did take some vacuum tubes off of the vacuum manifold (multiple hose connector?) when I put in the new Master cylinder, and now I'm kind of suspicious of the seals on those hoses now that I understand how the vacuum system works and what it is used for. It's all coming together, hopefully I'll get this issue figured out so I can drive out to the woods and do some camping.