73 chevelle brake problems.

by Dead Man Fri Aug 24, 2012 6:44 pm

The other day my brake light came on and I had just about zero brakes it would go all the way to the floor before it grabbed, so I bought new master cylinder and new brake booster, bled all the lines very well got all the air, the brake light is now gone and i have full pedal, but the pedal is hard and the car is not stopping well, its like the booster isn't working I have good vacuum on it and all so even tho its new I swapped it out for another new booster and im still having the same problems what could this be.

by 77ElClassic Fri Aug 24, 2012 7:11 pm

Sounds like you may have 1 or 2 wheel cylinders locked up. You could try jacking the car up and see if any of the wheels will still turn when someone applies the brake, or won't spin freely enough after the pedal is released. The other option may be a bad proportioning valve.

by 77mali Fri Aug 24, 2012 7:31 pm

Also worth noting: Did you bleed the master cylinder on the bench before the install? Most come with a bleed kit nowadays.

by Dead Man Fri Aug 24, 2012 9:29 pm

yes bench bled the master twice, and I know it will lock the back wheels up, when it was on jack stands would spin easy and lock them down when i hit the brake, and lock them down in the drive way. it almost seems like the fronts not working. and I have suspected the prop valve myself.

by badtemper44 Sat Aug 25, 2012 1:40 am

I actually had the same problem once. Went through everything you mentioned, replaced part after part, wheel cylinders, proportioning valve etc. Turns out I had a bad master cylinder right off the shelf! Boy was I ticked off, but at least I had a total brake overhaul! bounce

by dragons_lair59 Sat Aug 25, 2012 7:46 am

if the front lines are week (the short rubber to the caliper) they will expand and feel like no brakes. been there done that

by pila Sat Aug 25, 2012 8:01 am

Brake hoses have been known to delaminate internally, and acting like a check valve.......allowing flow in one direction and not the other. . Not likely that both front hoses would do it at the same time though. Of course the rear hose would affect both sides ....
Like mentioned here though, rebuilt master cylinders are notorious for not working correctly, and stretch or ballooning of hoses is not uncommon.
The good fix for new hoses are the braided stainless hose kits. They don't stretch, and make brake response better etc.

by Wallyuph Sat Aug 25, 2012 8:59 am

I have the same problem. I'm on my 3rd master cylinder and 2^nd booster. The rebuilt masters work of for a few weeks then they leak into the booster and the fluid wrecks the diaphragm in the booster. For me Orilies auto parts are the only one that carried the original style booster. I have replaced every thing but original steel lines running the body length. The new portioning valve also calipers and rear wheel cylinders rubber hoses. I have rear breaks but only once in while do I have fronts. Its so frustration that I have new after market 9” dual diaphragm booster and new large Bowl front and rear master Cylinder and a new self adjusting portioning valve going in shortly. I even went so far as to try an adjustable portioning valve in the original set up. Still have the problem.

Wally

by Dead Man Sat Aug 25, 2012 10:16 am

thanks for the feedback guys, im to the point I think im just gonna drive it some like it is, because hopefully by mid winter it will be coming off the frame and starting the rebuild, then at that point I will replace it all with better equipment. it would make so much more sense if the pedal was hard as a rock lol

by Wallyuph Sat Aug 25, 2012 1:20 pm

All three master cylinders and two booster have gone bad for me Here is what mine is doing right now. Not even 3 months old. Thats why I'm going all after market this time. Let alone hwo much break fluid I've gone through.

73 chevelle brake problems. Img_6111

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by Dead Man Sat Aug 25, 2012 1:57 pm

now thats a setup, I may do the same when its time to put all new after the frame off.

by Wallyuph Sat Aug 25, 2012 3:08 pm

what I'm taking out as it does not work, I eliminating every thing. I even have a brand new Pop valve on frame. Odds are if I swapped out booster and master cylinder it may work fine but I’m so fed up I’m not taking any chances. It ticked me off so bad a even bought a power break bleeder as wife is getting tired of “pump it up and hold it.”

Here is what’s going in now as I’ve read that line lock needs to go after pop valve not before. I have the same set up in my 56 Chevy that has 1969 nova front and break system in it and it works great.

[img]][url=https://servimg.com/view/17248508/47][img]

[img]][url=https://servimg.com/view/17248508/48][img]

[img]][url=https://servimg.com/view/17248508/49][img]

[img]][url=https://servimg.com/view/17248508/50][img]

73 chevelle brake problems. Img_6212

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by Wallyuph Sat Aug 25, 2012 3:12 pm

]

[/url]

]https://i.servimg.com/u/f34/17/24/85/08/img_6117.jpg[/img][/url][/url]https://i.servimg.com/u/f34/17/24/85/08/img_6116.jpg[/img]]https://i.servimg.com/u/f34/17/24/85/08/img_6116.jpg[/img][/url] 73 chevelle brake problems. Img_6115

][[/url]

by Wallyuph Sat Aug 25, 2012 3:13 pm

Sorry photos and me are not working well today.

by pila Sat Aug 25, 2012 7:19 pm

There's a brand name called Cardone that supplies NEW master cylinders to auto parts stores, like Advance Auto, and even through Summit Racing.

by Mcarlo77 Sat Aug 25, 2012 9:11 pm

I was going to suggest that, also. I was always told to NEVER buy rebuilt master cylinders.

by Dead Man Wed Jan 02, 2013 3:42 pm

well guys, after a few months of driving my brakes are back to doing the very same thing, so i think its time to replace the prop valve. this is the only place i can find them anyone know of cheaper or know about this place before i order.

http://www.carolinaclassictrucks.com/71-77_A-body-brake-valve.html

by 1973 454 MONTE Wed Jan 02, 2013 3:58 pm

i bought mine from advance back in 2000

http://www.ebay.com/itm/Disc-Disc-Left-Mont-Proportioning-Valve-Kit-Universal-Applications-/160927940046?pt=Motors_Car_Truck_Parts_Accessories&hash=item25780d7dce&vxp=mtr

http://www.ebay.com/itm/1971-1977-GM-Disc-Drum-Combination-Proportioning-Valve-Factory-Street-Rod-/350560569384?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3AMonte+Carlo&hash=item519f09c828&vxp=mtr

http://www.ebay.com/itm/76-77-78-79-Monte-Carlo-Brake-disc-drum-Proportioning-Valve-Power-Disc-Brake-/390499333184?pt=Motors_Car_Truck_Parts_Accessories&hash=item5aeb92f440&vxp=mtr

by Dead Man Wed Jan 02, 2013 4:06 pm

thanks that middle link was the ticket couldnt seem to find it when i looked lol, and i will try my local advance seems like they told me it was a no go when i checked a while back.

by Wallyuph Wed Jan 02, 2013 4:41 pm

I hope this works for you. I replaced the pop valve also on mine before swamping every thing out for after market parts and still had same problem.

I just installed a new set up in the 74 I just got. Did not even bother with any thing original style. Just went for what I know works. I also needed larger bowl as this car has disc rear breaks.

Here is what it has for set up.

[img] 73 chevelle brake problems. Breaks11

[/img]

by Dead Man Wed Jan 02, 2013 5:07 pm

I hope so to this is pretty much just to get me by until I restore everything. I will be going custom after that as you did.

by Wallyuph Wed Jan 02, 2013 6:12 pm

This way you can have a adjustable pop valve for the rear breaks. It take a few tries to get them dialed in.

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