proportioning valve, some ideas Options

[Trekkor]

I'll be covered in Motul before too long. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

Was kicking around the idea of opening up the prop valve and taking it all apart, rendering it a "tee".

Anybody done this?
Sure, just using a "tee" is easier. This is just something to do. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

Exploded view would be nice.

KT

[Jeroen]

buy a friggin' T (IMG:http://www.914world.com/bbs2/html/emoticons/slap.gif)

[Mueller]

it's been a while since I've seen the insides of one, but I think you might have difficulties getting the air removed.

[mightyohm]

Do a search here and also on PP. I have seen a diagram before. I think it was on PP. Someone had one completely apart showing all the components.

PS. A tee is significantly lighter. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[TravisNeff]

I would also think that it would be a bleeding nightmare the first go-round. aside from that, having a resivour (that is what it would essentially be) partway through the brake system - is that an OK thing to have?

[Series9]

Save yourself a bunch of trouble by going down to your local air-cooled VW specialist and buying a T for $5.

[McMark]

To clarify Trekkor's first post. He knows the T is "better" and has one on order. But let's think about what we could do. Is gutting the P-Valve a viable alternative?

It's not should he, but could he.

(IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif)

[bondo]

Haha, if you want something to do... I have a transmission that needs assembling! (IMG:http://www.914world.com/bbs2/html/emoticons/lol2.gif)

[Mueller]

exploded pic:
I see the two lines which I think go to the rear calipers....
now I cannot remember where the other line goes to.....

should be 3 total correct??

(IMG:http://forums.pelicanparts.com/uploads2/prop_valve_disassembled1082410190.jpg)

[lapuwali]

QUOTE (Mueller @ May 9 2005, 05:14 PM)

exploded pic: I see the two lines which I think go to the rear calipers.... now I cannot remember where the other line goes to..... should be 3 total correct?? (IMG:http://forums.pelicanparts.com/uploads2/prop_valve_disassembled1082410190.jpg)

The fluid as to come in somehow... (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif)

[eeyore]

I suppose any spaces in the proportioning valve body that can become air traps could be filled in with some chopsticks...

[Aaron Cox]

QUOTE (Cloudbuster @ May 9 2005, 06:19 PM)

I suppose any spaces in the proportioning valve body that can become air traps could be filled in with some chopsticks...

(IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/lol2.gif)

and mike....its the inlet from the MC (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[lapuwali]

The fluid normally comes in from the MC, and flows through those holes in the silver piston. Another passage in the housing also applies brake pressure to the silver piston to the right (in this pic) of the rightmost O-ring on that piston. This forces the piston to the left against that big spring, which closes off the holes in the piston. Eventually, the holes close completely and the rear brakes are cut off entirely.

You can also stiffen up the spring by placing some thick washers under that thin plate at the left end of the spring. This pre-loads the spring, so it takes more brake pressure to push the piston to the left, thus giving you more rear brakes. If you want to turn it into a big, heavy tee, then remove the spring and replace it with a bit of steel tube. You'll need to determine the correct length of tube, as I'm sure the spring is slightly compressed when everything is assembled, so you can't just use the free length of the spring.

I initially thought you could just remove the spring and the piston, but I think that will require you to add a lot of brake fluid to fill up that part of the housing that holds the spring. It looks like the piston normally seals that part off (see the leftmost O-ring), so only the area between the two O-rings has brake fluid in it, as well as the area to the right of the rightmost O-ring (note the O-ring on the end plug).

[boxstr]

Received these today from JWEST. Thank you.
CCLINTEETIME

[brant]

Trekor,

the only reason a person would do this would be due to stock type rules that do not allow you to run a "T" or run a proportioning valve...

surely that's not your motivation is it....
just teasing you
brant

[J P Stein]

If you have stock F&R brakes, why the" T"? I imagine that Porsche (Vdub?) seemed to think they needed the porp. valve for a reason.....like maybe F to R balance?

If you feel the need to change sumthin', put in an adjustable proportioning valve to balance future upgrades.

[root]

My "two-cents"; whatever modification you make always be sure to arrange the inlet side of a 'tee' on the bottom, unless you intend to reverse bleed the system, 'cause air bubbles like to go 'up' during bleeding. (IMG:http://www.914world.com/bbs2/html/emoticons/cool_shades.gif)

[914GT]

QUOTE (Mueller @ May 9 2005, 06:14 PM)

exploded pic: I see the two lines which I think go to the rear calipers.... now I cannot remember where the other line goes to..... should be 3 total correct?? (IMG:http://forums.pelicanparts.com/uploads2/prop_valve_disassembled1082410190.jpg)

Inlet is at the bottom of the casting where it bumps out. You can essentiall get the thing to act as a T by turning the screw on the end all the way in, causing the internal coil spring to bind and prevent it from regulating the pressure to the rear brakes.

[McMark]

Factory cutaway picture. There's a slight difference in the threaded hardline connections (same side vs. opposing sides), but the function should be the same.

[balljoint]

Does brake fluid sit in the cylinder with the spring or is it sealed off from the system? If it is full of fluid then it is already essentially an extra reservoir in the middle of the system. If it is just air in there then will it leak fluid to the outside if the seal breaks down or will it leak air into the system? If it is leaking air into the brake lines without spilling brake fluid to the outside then it becomes a difficult to detect source of air in the line.