Well I have tried to read first all of the articles on MC's and Prop valves before posting this, but now I'm more confused than before.

I'm installing a 9bolt rear from a 88 IROC, with the iron calipers. This is going into my 84 with rear drums. So I'm going to replace the MC and Prop. Valve with a 4 wheel disk set up (so far so good)..or should I use an adjustable prop valve with the new 4 wheel disk MC...if so how does the adjustable one mount? Of all of the adjustable prop. valves I have seen there is only the one port in and one out. Where as there are two lines coming from the MC itself to the old prop. valve.

Oh, and let me not forget the new e-brake cables.

Old stuff to some- Thanks, Ed.

 

Yeah, one line for the front, one for the rear. There is a single brake line going to the rear brakes which then tee's off at the rear axle to go to each caliper.

 

So then, out of the four wheel disk MC (two ports) the front line goes from the MC to the front disks and the rear line goes through the Adjustable prop. valve and heads to the rear wheel disks? Thanks, Ed.

 

It's my understanding that when you use an adjustable prop, you don't install the stock prop/combo valve at all. The fronts see full line pressure and then you dial in the rears to where you like them to be. This involves having to fit up new lines in place of the now missing prop.

I haven't done this but that's how I understand it.


Ed

PS: Do a search under "adjustable valve" in this forum...I got 184 hits on the subject.

 

Like eb said, thats my understanding of how they work.

 

Have fun figuring out the parking brake cables. I swapped out my broken 9 bolt for a 10 bolt and can't find cables.

 

Yeah what I did to fit the adjustable valve was to remove the existing proportioning valve and use a brass T piece for the front brakes. If you can get one with a mounting hole then drill a hole in the exsiting proportioning valve bracket and bolt it to it. Then do similar with the proportioning valve for the rear. because the adjustable valve is so heavy make sure you bolt it to the bracket or it will slowly damage your brake lines.

I would have to say that having the ability to get the rear pressure as high as is safe seems to work very well. I'm sure I noticed differences in the overall braking performance as I adjusted it. Just always make sure that the fronts lock before the rears and when testing it have plenty of room!

Si.

 

is that a 10 bolt drum? i have one i just pulled so i have cables avalible. if its disk can;t help ya there.