1965 Valiant brake woes

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scott_s

scott_s

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*Yes, I know there's a sub forum for brakes. There's a little more to this question though, and I'd like to get a few more eyes on this thread*

I picked up a 1965 Valiant convertible a couple of years ago. It was misrepresented, but I didn't inspect it as well as I should have before the purchase, and that's 100% on me. Whoever did the work on it was amateurish (a nice word for half assed). It has some good points, though; rechromed bumpers, new interior, carpet, top, tires, etc.
I did some tune up stuff, swapped over the correct carb, etc., in an effort to make it a reliable and fun cruiser.


20220708_081014.jpg

20220301_130515.jpg
 
One thing that's plagued me since day one has been the brakes. It's a drum/drum car, but it appears that maybe this car had a disc/drum combo at some point. It has a power brake booster/dual circuit master cylinder. It's possibly a GM piece. It also has an adjustable proportioning valve.

power mc.jpg

proportioning valve.jpg
 
I fail to see a question. At any rate, that's a drum/drum master cylinder. With the addition of the Speedway distribution block/proportioning valve, I suspect one of two things. Either like you say it used to have discs on the front, or someone was getting ready to do it.
 
Cool looking little buggy

Are the brakes not performing correctly?

Is it the setup that just seems off?

What would you want there instead?
 
here's a link to his original thread so everybody can be up to speed

www.forabodiesonly.com

Making the best of a bad situation

1965 Valiant. I'd like some thoughts and advice on my brakes, please. When I bought the car, it came to me with some issues and some "upgrades". I took it to a local shop that specializes in vintage cars. They fixed a leaky RF wheel cylinder, replaced a cracked drum (I believe it was the LF)...
www.forabodiesonly.com www.forabodiesonly.com
 
Or maybe someone just wanted a 2 circuit brake system for safety and there was no Tom foolery at all. It’s 60+ years old.
Now please state the question.
 
When I got the car, it had a leaky wheel cylinder. When repairing that, we found a couple of bad/cracked drums. I spent WAY too much money on drum brake parts trying to get it working correctly. It also has some new shoes on the front. The brake hoses look new-ish, and aren't plugged or collapsed because we can bleed fluid through them.
The brakes have been bled to death. The last shop adjusted the proportioning valve and that helped a lot.

I still have mediocre braking, at best. The car pulls to the right under braking, even after adjustment. No, I have not had the shoes ground to match the drums. I'm not even sure if there's a shop in my area that offers that. The pedal throw is long and not confidence inspiring. It also varies ....soft at first, then firmer after driving. Pumping the brakes doesn't make a difference; only driving. I attributed that to building vacuum, maybe?

Now, I new issue has popped up. I can hear air/hissing under the dash when pressing the brake pedal. I'm pretty sure the brake booster has developed a leak. At this point, I'm not sure what to do. The whole system seems cobbled together by the P.O. I have no clue what pushrod is in there, what master cylinder that is, etc.

I've spent enough money on the drums that I could have converted to discs.

The easy and cheap answer would be to ditch power brake stuff and install a drum/drum master cylinder. This one is from Pirate Jack, but RockAuto has even less expensive options (though I would need some guidance on which one to get).

MC1323 - 1960-1970 MOPAR A, B, E Body BENDIX 2660809 1" Bore Drum Brake Mopar Master Cylinder

Since I don't know what all is in there, I should probably get a new pushrod too, right? Again ... I could use some help on choosing the correct part.
Then, would you keep the proportioning valve or toss it and put in a stock distribution block?

All of that work to have "stock" drum/drum brakes.

The more expensive solution is to go disc. Rip out all of the crap forward of the firewall and order a kit. HOWEVER .... I just had the entire front end rebuilt, so I would be throwing away basically new lower ball joints and needing another alignment.
PLUS, I have 14" rims and SBP. I would need to make sure my wheels even clear. The tires are like new. I really don't want to add in the cost of new wheels/tires.

Sorry, for the long winded post, but I really need some guidance here. I've spent a fortune already. It's not so much the money at this point, but I just want to do it right ONE LAST TIME.
 
RustyRatRod said:
I fail to see a question. At any rate, that's a drum/drum master cylinder. With the addition of the Speedway distribution block/proportioning valve, I suspect one of two things. Either like you say it used to have discs on the front, or someone was getting ready to do it.
Click to expand...
that looks like a universal GM disc/drum (corvette) master to me. which is what most of those after market disc brake set ups come with.
 
junkyardhero said:
that looks like a universal GM disc/drum (corvette) master to me. which is what most of those after market disc brake set ups come with.
Click to expand...
Could be. But why on Earth would someone add a separate proportioning valve? I guess they wanted a lot of adjustment.
 
Syleng1 said:
Or maybe someone just wanted a 2 circuit brake system for safety and there was no Tom foolery at all. It’s 60+ years old.
Now please state the question.
Click to expand...
That's what I did to Vixen.
 
scott_s said:
When I got the car, it had a leaky wheel cylinder. When repairing that, we found a couple of bad/cracked drums. I spent WAY too much money on drum brake parts trying to get it working correctly. It also has some new shoes on the front. The brake hoses look new-ish, and aren't plugged or collapsed because we can bleed fluid through them.
The brakes have been bled to death. The last shop adjusted the proportioning valve and that helped a lot.

I still have mediocre braking, at best. The car pulls to the right under braking, even after adjustment. No, I have not had the shoes ground to match the drums. I'm not even sure if there's a shop in my area that offers that. The pedal throw is long and not confidence inspiring. It also varies ....soft at first, then firmer after driving. Pumping the brakes doesn't make a difference; only driving. I attributed that to building vacuum, maybe?

Now, I new issue has popped up. I can hear air/hissing under the dash when pressing the brake pedal. I'm pretty sure the brake booster has developed a leak. At this point, I'm not sure what to do. The whole system seems cobbled together by the P.O. I have no clue what pushrod is in there, what master cylinder that is, etc.

I've spent enough money on the drums that I could have converted to discs.

The easy and cheap answer would be to ditch power brake stuff and install a drum/drum master cylinder. This one is from Pirate Jack, but RockAuto has even less expensive options (though I would need some guidance on which one to get).

MC1323 - 1960-1970 MOPAR A, B, E Body BENDIX 2660809 1" Bore Drum Brake Mopar Master Cylinder

Since I don't know what all is in there, I should probably get a new pushrod too, right? Again ... I could use some help on choosing the correct part.
Then, would you keep the proportioning valve or toss it and put in a stock distribution block?

All of that work to have "stock" drum/drum brakes.

The more expensive solution is to go disc. Rip out all of the crap forward of the firewall and order a kit. HOWEVER .... I just had the entire front end rebuilt, so I would be throwing away basically new lower ball joints and needing another alignment.
PLUS, I have 14" rims and SBP. I would need to make sure my wheels even clear. The tires are like new. I really don't want to add in the cost of new wheels/tires.

Sorry, for the long winded post, but I really need some guidance here. I've spent a fortune already. It's not so much the money at this point, but I just want to do it right ONE LAST TIME.
Click to expand...
I completely rebuilt the drum brakes on my 64 Valiant right after I got it. I've since added a disc brake master cylinder and proportioning valve but still retain the drum bakes. I have K/H 4 piston caliper disc brakes for the front that I have not installed yet, but for now she stops really well. Especially considering she only has 9" drums.
 
RustyRatRod said:
Could be. But why on Earth would someone add a separate proportioning valve? I guess they wanted a lot of adjustment.
Click to expand...
judging by the junky mismatched hardware and the "adjustable" push rod featured in the other post, i'd wager a guess that there was a fair bit of tom foolery going on.

your earlier guess might've been spot on. maybe they were gettin' ready to do discs? or they just wanted power and that was the easiest way to get there-- open up the catalog and fire up the credit card, press that easy button.
 
junkyardhero said:
judging by the junky mismatched hardware and the "adjustable" push rod featured in the other post, i'd wager a guess that there was a fair bit of tom foolery going on.

your earlier guess might've been spot on. maybe they were gettin' ready to do discs? or they just wanted power and that was the easiest way to get there-- open up the catalog and fire up the credit card, press that easy button.
Click to expand...
Who da hell knows?
 
I'm pretty sure that whatever is going on with the booster is causing some idle issues, too. It's surging at stop lights with my foot on the brake. It acts like a big block with a lumpy cam!
I just checked the timing, idle adjustment, etc. yesterday. I guess a vacuum leak from the booster could cause this?
 
scott_s said:
When I got the car, it had a leaky wheel cylinder. When repairing that, we found a couple of bad/cracked drums. I spent WAY too much money on drum brake parts trying to get it working correctly. It also has some new shoes on the front. The brake hoses look new-ish, and aren't plugged or collapsed because we can bleed fluid through them.
The brakes have been bled to death. The last shop adjusted the proportioning valve and that helped a lot.

I still have mediocre braking, at best. The car pulls to the right under braking, even after adjustment. No, I have not had the shoes ground to match the drums. I'm not even sure if there's a shop in my area that offers that. The pedal throw is long and not confidence inspiring. It also varies ....soft at first, then firmer after driving. Pumping the brakes doesn't make a difference; only driving. I attributed that to building vacuum, maybe?

Now, I new issue has popped up. I can hear air/hissing under the dash when pressing the brake pedal. I'm pretty sure the brake booster has developed a leak. At this point, I'm not sure what to do. The whole system seems cobbled together by the P.O. I have no clue what pushrod is in there, what master cylinder that is, etc.

I've spent enough money on the drums that I could have converted to discs.

The easy and cheap answer would be to ditch power brake stuff and install a drum/drum master cylinder. This one is from Pirate Jack, but RockAuto has even less expensive options (though I would need some guidance on which one to get).

MC1323 - 1960-1970 MOPAR A, B, E Body BENDIX 2660809 1" Bore Drum Brake Mopar Master Cylinder

Since I don't know what all is in there, I should probably get a new pushrod too, right? Again ... I could use some help on choosing the correct part.
Then, would you keep the proportioning valve or toss it and put in a stock distribution block?

All of that work to have "stock" drum/drum brakes.

The more expensive solution is to go disc. Rip out all of the crap forward of the firewall and order a kit. HOWEVER .... I just had the entire front end rebuilt, so I would be throwing away basically new lower ball joints and needing another alignment.
PLUS, I have 14" rims and SBP. I would need to make sure my wheels even clear. The tires are like new. I really don't want to add in the cost of new wheels/tires.

Sorry, for the long winded post, but I really need some guidance here. I've spent a fortune already. It's not so much the money at this point, but I just want to do it right ONE LAST TIME.
Click to expand...
besides your whole host of other issues-- seemingly attributable to the power booster-- why spend $75 for a master? get thee to rock auto and pick you one up for half that. 67 valiant, any of them will suffice.

i don't know what's up with the push rod you've got cooking. it might work, or it might not. but i'd at least try it and see.

btw, the later model discs are now available with small bolt pattern rotors that will fit *some" 14 rims. so swapping to discs might not be that expensive of a proposition for you. or, at least a marginally less expensive one.
 
Yes it can. I would personally just go back to manual brakes. Bet it has 9" drums. Works well for a cruiser, not like todays stopping at all.
 
scott_s said:
I'm pretty sure that whatever is going on with the booster is causing some idle issues, too. It's surging at stop lights with my foot on the brake. It acts like a big block with a lumpy cam!
I just checked the timing, idle adjustment, etc. yesterday. I guess a vacuum leak from the booster could cause this?
Click to expand...
yes. 100% it could, and will.
 
scott_s said:
I'm pretty sure that whatever is going on with the booster is causing some idle issues, too. It's surging at stop lights with my foot on the brake. It acts like a big block with a lumpy cam!
I just checked the timing, idle adjustment, etc. yesterday. I guess a vacuum leak from the booster could cause this?
Click to expand...
Sounds like the booster diaphragm is ruptured causing a manifold vacuum leak.
 
A way to arch the brake shoes for each drum, since finding a arching machine today is almost impossible is take some line board sanding PSA sand paper stick it on the surface of the drum loosely adjust the shoes and spin the drums while lightly adjusting the shoes out to arch them. When done remove the psa and final adjust the brakes. Sounds hard but super easy.

@mobileparts might have the master needed.
 
Before ordering a disc brake kit I'll pull a wheel and measure correctly, but it appears that I have the deeper/wider wheels, so fitting front discs shouldn't be an issue, right?
These are 10" drums with the 2.25" shoes.

20240912_083827.jpg

20240912_083833.jpg
 
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