I just had a brake conversion done on my 67. The pedal was so tight and the rear brakes would start to drag when the car got warmed up. I did a search and found out the rod/clevis for power brakes should be through the bottom hole on the brake pedal and manual brakes go in the top hole.
I changed mine to the lower hole, the pedal pressure is much better now and no rear brake drag. But the pedal return is weak. The factory assembly manual I have doesn't show a return spring like manual brakes have. Is this correct?
If not and power brakes also have a return spring, how is it hooked up? Trying to hook up the extension and spring to the bottom hole doesn't seem to work because of the brake light switch and the upper hole now has no pin to fasten the extension piece that hooks to the spring. ....or is there another cause to the weak pedal return that I didn't notice when the pedal was so tight?

Thanks in advance for any help. I am dying to figure this out so I can get my baby on the road!

It sounds like you're missing the extension tab for power brakes.. No spring return on pwr/brakes.

Click here
http://www.camaros.net/cgi-bin/forum/ultimatebb.cgi?ubb=get_topic;f=7;t=004120

http://www.camaros.net/forum/ultimatebb.php?ubb=get_topic;f=7;t=004179#000000

[ 06-21-2004, 10:12 PM: Message edited by: RamJam ]

Thanks for the info RamJam. Now I just have to decide if I want to do an extension on the rod or try to find the extension for the brake pedal. I probably will do the rod extension first as I am not sure where to locate the brake extension and really don't have the time to try to fabricate one.

Anyway, thanks for the help.

Victor

I got mine off a 71 Nova in a junk yard. I'd check some local junk yards. I'm sure the same part was used on more than Camaro's and Nova's upto around 1975.

You could probably ask this guy to find one for you also.

http://www.camaros.net/cgi-bin/forum/ultimatebb.cgi?ubb=get_topic;f=24;t=000329

RamJam, thanks for the info!

I did the rod extension as a temporary fix but will try to get in touch with your contact for the extension bracket. I still have slow pedal return when the car is on and booster is recieving vacuum from engine, but when I turn the engine off, the pedal tightens up really nice after pumping the pedal 3 times to get rid of the vacuum reserve. I did some more trouble shooting and found that the white plastic sleeve mounted between the booster and firewall has a visible crack/split in it.

Is this what is causing the slow pedal return?
If so, can this be replaced or do I need a new booster? (I haven't found any of these sleeves for sale in any of my catalogues.

Thanks again for your help.

Victor

I don't think it's the boot it's just to keep dirt out. Mine had a crack in it too I got it from junk yard. I filled the area with silicone caulking, no problem. I don't know what else to tell you about brake pedal feel.

Rick's First Gen has them here's the link. It doesn't go right to the page so click on Booster & Master Cylinder on the left. Scroll down you'll see it.
http://www.rickscamaros.com/cgi-local/SoftCart.exe/online-store/scstore/catalog_brakes.htm?L+scstore+lrvs4850ff1fc81f+1088 153902

http://www.rickscamaros.com/online-store/scstore/graphics/pb-18.jpg

RamJam Thanks again!

I cant tell you how much I appreciate all the help you and others have given me already!

If the dust boot crack doesn't affect the brakes function, I will use some silicone to seal the crack. I had thought about doing that but didn't know if it would affect brake function.

I still need to trouble shoot this some more. Could it be I just got a bad booster or check valve on the booster since the pedal is tight when the engine isn't running (no vacuum reserve). With the engine on, pedal travel is much further, much looser and has the slow return.

Thanks again for your help.

Victor

If you have the brake warning light coming on, you have air in the system and that's causing extra travel and perhaps slowing the return.
Make sure there is nothing blocking the flow of air into and out of the booster through the plastic tube you say is cracked. There is a foam or felt pad around the pushrod that muffles sounds from the booster but make sure there isn't something else blocking air flow.

The power booster won't return as fast as a manual brake pedal due to air flow.
David

Hey guys,

I have been working on the brake system this weekend and have got the parking brake set properly, re bled the lines, and checked the foam/sponge dust protector on the back of the power booster. there were 2 of the foam discs so I removed one of them. the brake return is better now and the pedal seems slightly tighter with the engine running.

My only problem now is the rear brakes start dragging somewhat after the car has been driven about 20 minutes. After letting it set overnight, I checked the brakes this morning and the rear brakes were dragging with the car off, but when the car is started the rear wheels spin freely. I am now thoroughly confused as I would think it would be the other way around (brakes drag when car started, spin free when car is off).

Any Ideas on what is causing this?


Thanks,

Victor

I'm glad it's working better but sorry it's still not right. I really can't help you more with the prob you have now. David will prob be the best help now with this problem. Good luck!

I went back to square one to figure what was causing my brake problem. So I took Wise David's advice and tried to determine what could be causing air in the system. So I looked at the system from front to rear looking for connections with bad seals, leaks in the line, checking everything! Everything was fine. The brakes had been bled repeatedly, with not the slightest air bubles coming out. So I thought where could air be trapped in the system that I wasn't able to bled out. I did have all new stainless brake line that I bought, maybe Air was in the top of a bend or something like that......and then it hit me, when I first got the system on I noticed that one of the rear calipers had the bleed screw facing down. I thought wow! I have never seen that before, and then didn't think anything more about it.

Flash.....If the bleeder valve is facing down, air trapped inside isn't going to be able to get out of the system unless you take the caliper off and bled it with the valve facing upward....D'oh, what a Homer move. I should have picked up on that right away, but... I didn't. Rookie.

Since I had the pushrod in the wrong brake pedal hole and a cracked dust sleeve, I just knew there had to bewas some problem with the master cylinder/booster. Then after reading David's post, I was like, he's right, air in the system is the obvious cause for the pedal spongyness, slow return, etc.

So to make too long of a story shorter, the company I got my brake kit from shipped two right rear calipers with my system, and I didn't question it, because I thought, this is what they sent me...it must be right. I contacted them and told them what happened and they immediately shipped me a new left rear caliper, no questions, no problem, painless.

Moral of story........check kits to make sure all parts are what they are supposed to be. D'oh.

David thanks for your help!!!!!!! (Thanks for yours too RamJam!)


Victor

You're welcome. I'm glad you got it. graemlins/thumbsup.gif

Okay one problem solved, now I have another I need help with. Got the new caliper on (the correct one) bled the system, again. Now rear brakes seem to be drawing way too far away from the rotor when they are not applied. Is this normal? Might there be a check valve (Proportioning valve) that not working and taking off too much pressure (preload)off the rear brakes. Would tightening the emergency brake help this by keeping the pads closer to the rotors. Or maybe adding and adjustible proportioning valve to the rear brakes. David, RamJam any ideas? I need your expertise....again. Sorry to be such a pain but brakes...I never was very good working on them, but I know they are extermely important so I just want to make sure i am getting this right.

Thanks again,

Victor

P.S. Happy Independence Day

You could add a 10# residual pressure valve to the rear line. Paul, owner of Hydroboost, discusses this on pro-touring.com.

Rick,

Thanks for the info and the great link. Do you know where yor get these residual pressure valves? From brake kit manufactureres? Restoration catalogues? Junk yard?

Again thanks for the info!

Victor

Did some research and found Wilwood residual pressure valves. They have both ten pound and two pound valves. They say you need the two pound for discs and the ten pound for drums. I am thinking of trying the two pound ones first and see if that does the trick, (worried about dragging). What do you think? This is a new conversion so I am going to call to see if the kit is supposed to have an RPV already in it and maybe it isnt working. (in combination valve or somewhere else.)

Thanks again for your input.

Victor

When you say they pull to far back, what symptoms are you experiencing? Paul recommended a RPV when there was additional pedal travel on the first pump of the brakes. In my front disc/rear drum setup I don't have one and the pedal is nice and high/firm.

Hey Rick,

Happy 4th of July! I Did some research on brake system kit I got and the combination valve at the master cylinder has the metering, proportioning and residual pressure valve in it. Their online trouble shooting section says the residual pressure valve is probably stuck open and they detail; what to do. I'll update after I get to work on that. One other interesting thing I noticed on troubleshooting is that since the master cylinder is tilted, air could get trapped in the piston and cause a spongy pedal etc. I'll check that after I trouble shoot the residual pressure valve.

Again Rick, Thanks for your help!

Victor

Many of the rear calipers self-adjust by use of the parking brake. You have to apply the parking brake repeatedly to cause the rear calipers to adjust properly. Just pressing on the brake pedal won't work. Also if you don't have positiraction, your rear axles may have too much end play and knock back the rear brake pads. The axles these brakes were made for had outer axle bearings that kept end play at near zero. The typical non-posi GM C clip axles have a LOT of end play.
David

David,

Thanks for the info. I thought the emergency brake had something to do with adjusting the pads. How many times do you typically need to engage the parking brake to get the rear discs adjusted? I knew axle travel might knock the discs back but I thought that was one of the function's of the residual pressure valve. Right now brakes are bolted to a 68 ten bolt with 2.73 open gears. But I do have my 67 twelve bolt with a 3.08 posi ready to bolt on, I was just trying to get the brakes working properly before I threw another variable in. Should I go ahead and do the rear end switch? The rear has been completely rebuilt, New Eaton Posi carrier, new ring & pinion , new heavy duty axles but still uses the c clips. How much less play will there be on this on compared to the one in the car now?

Thanks again David, and happy 4th of July!

Victor

I'd try applying the parking brake about 10 times and see if things improve. If they do, you might try another 10 times.

Your 12 bolt with posi probably has .030" of end play if new, while the open diff probably has over .150"
End play won't cause knock back unless you are driving. If you are having knock back a 2 psi residual valve wouldn't hurt anything but probably won't improve things a lot either.

There are 10 psi residual valves, but they are high enough to cause pad drag.
David

An update for those interested.

The residual pressure valve on the combination valve was stuck in the open position. Fixed that, rebled the system and set/released the parking bake about twenty times. Wow! The pedal was tight and it stops so quick it makes me think bout getting a shoulder belt and headrests. Took it for a drive, (hard drive with cornering) and the endplay of the axles on the open 10 bolt caused the brake light to come on. The car then needed a little more pedal pressure to stop but still was a so much better than stock manual discs/drums. Resetting the parking brake adjusted the rear brakes and the brake light on the dash went off.

That would probably have been okay, but I had this nice rebuilt 12 bolt posi just waiting to go in and this was the excuse I needed to go ahead and switch the rears out. I had planned to do the changeover this fall/winter. (Also the fact the 10 bolt was geared so high I never got the car into 4th gear unless I was on the highway.)

I got the 12 bolt in. No more endplay, no more brake light on dash coming on and having the re adjust the rear discs every time I take a corner hard. The conversion was such a pain but now that its done I couldn't imagine running a stock set up. I know that might make some purists cringe, but I am keeping the old parts and I'll never sell this car anyway!

Any way I think this is the best upgrade to do on a first gen because I always felt the braking system was the weakest part of the car. Not anymore!

David, Rick and RamJam,

Thank you, I could not have done it with out all of your help!


Victor

Glad it worked out. Thanks for the feedback!