86 Jetta rear brake proportioning valve

[82vdub]

This is the proportioning valve that's back by the rear axle under the car. Anyone ever delete one of these on the car? Mine's rusted, likely not functioning and I broke a brake line. If this has been done before, was just a brake line "T" installed in it's place?

[Fatmobile]

You need some kind of proportioning. The fronts need more pressure than the rears because that's where the weight goes when you stop.
You shouldn't just delete it.
Did you check the price of a new one? I don't remember them being that spendy.

[82vdub]

I figured that. After I posted this message and at the end of my work day I looked on ebay and found them on there for $100. The mechanic I brought the car to said that he couldn't get a new one, so I just left it at that. I've got to get under the car and figure out what I'm going to do on this. There's two more months of cold weather where I need the car running for that time. The older I get the less enthused I am to work on rusty brake lines, or other things that are rusty for that point too.

[vwtyp133]

The real overall front-to-rear proportioning job is done up front, on-or-near the master cylinder.

That rear "proportioning valve" (don't recall VW's actual name for it right now) is more of a fine tuning type of device to allow more or less pressure to the rear brakes according to the heavier or lighter load you have on the rear suspension, as indicated by the height of the car's butt.

If your rear loads don't change much, it's likely that the load-sensitive rear brake pressure adjuster mechanism froze in its 'normal' position. So as long it still permits fluid flow to the rears, and your loads don't change radically... you're probably OK. My Dasher has Air Lift air bags that can be filled to keep its butt from sinking, but, of course, that defeats the function of my VW's rear 'load sensor'. OTOH, it still does quite well - loaded or not, even with the tongue weight of a trailer back there.

Long story short... if the fluid/pressure still gets to the rears & nothing leaks, I wouldn't sweat it too much! YMMV

J.R.
SoCal

[82vdub]

According to the Bentley, it's either got a proportioning valve at the rear axle, or two proportioning valves located on the master cylinder. Mine has it by the rear axle.

This past Saturday, I got all the old rear brake lines pulled and new lines installed. That was a lot of work. I've got all the fittings loose and nothing buttoned up yet. Ran out of light, and it's going to be cold and wet for at least a week, so I won't finish this for a while yet. I got the old proportioning valve out and amazingly got all the fittings out of it. I'm going to reuse it, unless it leaks or otherwise can't get it to seal properly with the new fittings.

I'd like to pressure bleed my brake system. Without people sending me links to pressure bleed tools, I need to rig up something. I have a vacuum/pressure can that I use to evacuate fluids and transfer fluids around a vehicle. I can use this to build pressure in the brake system, without issue. The problem I do have is that I don't want to drill a hole in my master cylinder cap. Does anyone have a common solution that I can rig up for a cap to use in place of the stock cap? I've got to be able to drill a hole in it and rig up a line to it, and I have to be able to hold some pressure for a few minutes or so. Not a really long time, but enough to push fluid around. Any thoughts?

[mtran]

I call friend to press pedal.
Never use that tool but I think you can use vacum no pressure.

[82vdub]

I have a vacuum brake bleeding system, and it has it's drawbacks. I want to pressure bleed the system this time since the entire system was emptied of fluid.

[wmasscaddy]

Mine has the cap from a sports water bottle with RTV smeared into the nozzle. So there is at least one other thing out there with the same thread.

[VW cat]

I took that valve off a 97, it was leaking a little. Works fine without it.

[mtran]

Works fine without it.

Mine too,but remember you get full pressure ALL time,so easy on rain/snow.