Muswagon

Got the car rolling, the cam is a bit more severe than the guy told me it was, of course the guy lied about almost everything to the point I almost made an Ebay claim. Anyway. it was a factory power brake car, and we converted it to discs in the front. The master cylinder, brake booster, lines, rear brakes (all parts including drums) are all brand new. Problem is there are no brakes. The pedal is as hard as a rock and barely can stop the car if you stand on it. We are assuming its the lack of vacuum (the cam is silly), cuz there sure aint much vacuum there. We are going to use a vacuum tester/pump to check, if that is the issue, whats the solution (vacuum canister or electric vacuum pump, or what else is there?). Here is a tiny video of it rolling around. Sounds pretty good even though it looks like the pink panther with a really bad bladder infection.

http://www.youtube.com/watch?v=Daqz2QbG23o

78D200

Install a cam that is more vacuum friendly or add in a vacuum pump. If you had drum front brakes, did you add in a proportioning valve too?

Polaradude

Holy bumpstick, that thing is barely runnin, no wonder no brakes, either that or things weren't bled right. Nice ride though.

67 GTX

2x on what polara said
have you tried re-bleeding the brakes?

theomahamoparguy

Well, there's also the hydraboost system [works off your power steering pump if you have one].
I would double check your lines though. It sounds like the pressure is trying to fight itself [maybe in the valve] or Line routing or parts incompatibility.
must use 'disc' type prop. valve like 78D said.
Option 2; manual disc brakes. (no power assist)

67 GTX

if you have power brakes, the cam is probably too hairy, so you cant build up enough pressure

Muswagon

Added a vacuum pump, made it a bit better, but still no usable brakes.

All brake parts are new, has proportioning valve installed. SSBC front disc brake kit, so it has the right master cylinder. New booster. New rear brakes, drums, lines, everything is new.

The one question is the distribution tee, the one where the lines go to from the master cylinder then to teh rest of the car, is THAT piece supposed to be different on disc car from a drum car

Muswagon

Sorry, I am an idiot. I misunderstood the guy that is working on my car. Here is the story. I bought an SSBC kit, which instead of a new proportioning valve (what I refered to as a distribution tee, which I guess is techincally correct ) they including an adjustable valve that installs after the original valve.

So, still having a drum brake valve on there must be my issue, not sure why SSBC says it works with the included valve, as it certainly does not.

78D200

If they installed an adjustable valve after the proportioning valve....... well..... that just doesn't make sence to me. If the adjustable valve is set correctly (which would take some time to do I would think) then you shouldn't have a problem. [Have you looked for any leak (while I am thinking about it)?] I would think that you would replace the proportioning valve with the proper one or an adjustable valve, not both.

An adjustable valve and proportioning valve are basically the same thing minus the fact that you can adjust the adjustable valve and can not adjust the proportioning valve.

Yes you need to change the proportioning valve if you are going from drum/drum to disc/drum or to disc/disc because disc brakes need more pressure to work. Also with drum brakes, you have about 7 PSI being applied to keep the seals on the wheels cylinders from colapsing on themselves. If you installed disc brakes inplace of drums, then your disc brakes will be dragging all the time.

scotts74birds

Disc brakes require more fluid volume

Muswagon

Set at 50/50, the rear brakes lock and the fronts dont brake much (they do in the air, but not on the street). Set more to the front, little in the back and similar nothingness in the front. Seems to me that an adjustable valve after the drum distribution block is a dumb idea by SSBC. I will ditch the drum valve/block and the adjustable valve and go with a normal proportional valve only for disc/drum setup. Found one on summit, $75, not sure if that is a good price. None locally. I am looking under a GTX valve, as they had discs in front. What year will the valve work, as in, can I use a '78 Cordoba valve, as I think they still might be at auto shops.

Also have a carb problem. Took the part number off the carb, it is a 650 DP Holley. I want a nice 750, mech secondaries (as my low vaccum will surely cause issues with vacuum secondaries), and elec choke. Opinions? Prices?

Muswagon

This is the one in the kit inline with the orginal distribution tee

This is the one that I will buy to replace both the stock tee/valve and the in/out add on from SSBC

Muswagon

The one in the bottom picture is the I am buying from summit.....

theomahamoparguy

I know you guys are going to disagree with me but I think the mopar style of disc prop valve does next to nothing as far as proportioning is concerned. It is more of a delay valve if anything. You could just run the rear brake line straight from the master and just use a t for the front brakes. Yes, use your adjustable prop valve in the rear line. You dont need the residual valve either if the rear wheel cylinders have the expander "springs" in them. {most do nowdays}. (I read about this in MOPAR ACTION, "E-Burger" hisself said it {i think he cut a valve apart to look inside}. What really evens the brakes out is the pressure in the lines. Use a smaller wheel cylinder in the back and it will keep them from locking up and put more pressure to the front at the same time. {15/16 inch wheel cylinder from a 1/2 ton dodge pickup/early eighties}

Muswagon

So, decided just to use a rregular tee from the front brake section of the master cylinder, then the rear with the adjuatable valve on it as per suggestion above and the local speed shop. When bleeding the front there is just a dribble, my thoughts are when you bleed front brakes it should hit the inner fender well with some force. Needless to say the brakes dont work so hot.

unhooked the vaccum pump and tried the car like that to see if the booster was the issue, the brakes were worse but not by much.

The master cylinder is an easy change, the booster not so much, so guess which one I am trying first.

Man, this brake thing really sucks my butt hole.

theomahamoparguy

If ther is just a dribble, that is not right. Are the steel lines clogged up.
Test using compressed air. [This happens more than you think]

Also i was thinking, what size drums do you have in the rear 11 or 10??

Muswagon

Dont know the size of the drums off hand, would that make a difference with the front and rear system not connected anymore through a distribution block? The lines are brand new, but worth a try to see.

Did not try bleeding at the master.

theomahamoparguy

No, the rear drum size could effect the brake bias [slightly], Im trying ideas in my head to give the most pressure up front where it will do some good. You should only need 10inch drums in the rear with the small wheel cylinders.
Ya gotta bleed the master cylinder though, very important.(you can do it while its on the car though with an assistant)

Make sure all you brake lines are clear, front and rear. The damn thing should almost bleed themselves. (i've done it that way as a matter of fact, its called gravity bleeding, but ya gotta have clear lines)

Muswagon

tried a new master cylinder, now I have pressure. The one I took off was a brand new one that was included in the SSBC kit, kinda surprised. Now I have brakes but no power assist still, the new booster I bought is doing nada. Tons of vacuum, I have a brand new vacuum pump and we tested the vacuum to make sure.

Bad parts that were bought new so far are;

Alternator (was dead and also had MASSIVE shaft play)

Master Cylinder (no pressure)

Booster (not boosting)

VERY bizarre!

Oh, and my power steering went on the way home from the guy who is building the car, so I eithet lost the belt or the fluid

78D200

I have seen new and reman MC not seal right. I've had it happen to me actually.

Seems like it's just one thing after another for ya Mus. I feel for ya.

Muswagon

Apparently there are two different boosters, one for disc and one for drum, Piston Ring accidently gave me the one for drum. I know there is a massive difference in the master cylinder, but in the brake booster?? Maybe thats why I have no boost??

theomahamoparguy

Ive not heard of that either. Try it, make sure the pushrod going into the back of the master mates up correctly [length wise and diameter]. Also the rod going into the booster from the pedal. Does it use a retainer? double check. [I hope there isnt a booster/disc specific pedal setup.]

Muswagon

The new booster came in, its TWICE the size as the first one I bought, its a Satellite part number and the first one was a Roadrunner part number. Adjusted the rod, set er up, and now I have brakes There is a vacuum delay sometimes, and you can hear the pump going on and off, I think I need a vacuum canister to store up enough vacuum for 'on demand' use.