Team Camaro Tech banner

Problem bleeding front brakes

5K views 11 replies 7 participants last post by  ohcscott 
#1 · (Edited)
I've installed all new brake lines and master cylinder with disc front and drum rear. I used the old distribution block and purchased a used proportioning valve on e-bay. The seller claimed it worked. I installed the proportioning valve between the master cylinder and the front brake portion of the distribution block as shown in the build manual although everything I have read about proportioning valves says they go in the line to the rear brakes. '67s were different I guess. All lines fit as they should anyway. I have been able to bleed the rear brakes and the passenger side of the front but can only get a small amount of fluid from the driver side. When the brake is applied all wheels lock except the driver side. Could the proportioning valve be sticking? I don't think so. Could there be something blocking flow to the driver's side in the distribution block? More likely, but I cleaned it thoroughly before installing it. Does anyone have suggestions or ideas?

Just returned from loosening line at distribution block and depressing pedal. Shot fluid all the way to the radiator support. Maybe something stuck and has now come loose. Will try additional when I get some help.
 
#2 ·
The bullet shaped valve for the front brakes is not technically a proportioning valve. It's a front brake metering, or "hold off" valve which delays front brake activation until the rears can overcome return spring pressure. It completely cuts flow to both front brakes under light pressure. Some cars came with an additional square-ish valve in the rear line to regulate rear pressure in proportion to front during hard braking.

anyway,
It sounds like you have some blockage in the driver's side, as you suspected, somewhere after the dist/. Just keep going on the line you started, and you'll figure it out.
 
#3 ·
I think I would try something simple and replaced the bleeder valve on the driver side to make sure something just isn't clogging it.
 
#4 ·
I had a problem that I just figured out on my drivers side rear disc brake. Tried everything under the sun. Installed a new 4 wheel disc brake conversion and it seemed like I was getting no where. For 2 weeks of off/on working on the problem, it ended up being a bad banjo bolt. There was some flow through it, but not enough to be able to properly bleed out the drivers side. I had taken off the caliper, blew out the bleeder valve and the caliper, pulled all lines off and blew brake cleaner through them. Ended up switching the calipers from side to side. All the frustration for a $4.50 bolt...
Check the bolt just in case.
 
#5 ·
Can I ask what is a banjo bolt and where is it located? I have been working my brakes and bled them. all new calipers on front disks, new everything in back drums. brakes felt firm till we started the car and the pedal goes all the way down. The Vacume hose is hooked up, and I could not find any leaks. I have not checked if I am getting vacum but it is sooo hot in the barn. Im guessing the banjo bolt is the one where the fluid enters the caliper?
 
#6 ·
i had the same problem , i found in a chiltons book the answer

" important: on cars with front disc brakes , it will be necessary to hold in the metering valve pin during the bleeding process . The metering valve is located beneath the master cylinder and the pin is situated under the rubber boot on the end of the valve housing. this may be taped in or held by a helper"
i cant scan it to post but this is word for word out of the book.
hope it helps
 
#7 ·
The banjo bolt connects the flex hose to the caliper. (not used OEM 67-68).

It is a hollow bolt with a hole inlet/outlet to let the fluid flow from the line into the caliper.

Here is a pic link of a typical banjo... hope the link works:


It's also used on a lot of fuel systems nowadays.
 
#8 ·
Thanks for the info. I had also replaced both banjo bolts as well as the lower hoses that they go threw. I had to because the calipers that I bought took a different size banjo bolt than what was on the car. They are calipers for a '80 camaro. I had to replace them because one of the bleeder bolt holes was plugged with a regular bolt. upon further inspection, it was because the threads were stripped. We could not identify what model those calipers were from so we just matched it as closely as possible with a '80 camaro caliper. It fit perfectly but had smaller banjo bolt holes. Well I had to go back to O'Rielly's anyway.
Thanks 6d7 rs for the info on the metering valve. I may have to re bleed the brakes holding the metering valve.
 
#9 ·
Well here is a new dilemma. I do not have the combo valve that had the metering valve built in. What I have is original valve that does not include a metering valve. By looking at the Book diagrams there is a separate metering valve that is in line before it gets to the splitter that the book calls a switch (or some refer to as a proportioning valve). . My setup is missing the separate metering valve.
My question is should I look for this valve or go to a combination valve that I can get on line for 90.00 at year one.

Classic industries has the same valve for 160.00. the only difference is that they include the bracket, screws and 2 lines that come from the master cylinder.
 
#10 ·
METERING VALVE : I bought mine from Classic but The Right Stuff sells it as well. See my post at the end of http://www.camaros.net/forums/showthread.php?t=78801
From Classic its PV68 67-69 DISC BRK METERING VALVE

Issue with combination valve is the stock lines will not fit it, requiring you to flare some brake tubing and get crafty.
 
#11 ·
I found a site from the thread you provided called Pirate Jacks. They sell both the combo valves and metering valves cheaper than the other sites I have seen.
http://www.piratejack.net/proportioning_valves.html
It looks like it would be a lot simpler and cheaper to go with a combo valve kit. I can get a crome one for 95.00 or 77 for brass. like you said, I will have to do a little plumbing to get all the lines right.
I see that they have a 360 loop in all the pics I have seen that are spaceing just so under the valves. Is there a reason for that?
 
#12 · (Edited)
The loop is for flex.
The disc/drum combo valve in the pic-link (PV2) is a 9419 valve... about $50 from delco or GM (delco 1721353 or GM 25509419) suitable for your car, and you could actually upsize the rear cyls to 15/16" bore (75-81) with that valve. Stock on Nova, Firebird, Camaro, many other cars and trucks, it is the most commonly used valve AFAICT, even with widely different sized brakes and weights.

You will need to change line routing and fitting sizes.

Edit:
recalling from other posts...
piratejacks uses parts from http://www.mbmbrakeboosters.com/
these parts may show a "MADE IN USA" stamp and may NOT be delco or GM products as shown in picture.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top