1956 Buick Power Brake Rebuilding

[NickG]

*I had this posted in the 'Technical' section, but have since had it removed and relocated here. I believe it is more pertinent here*

 

G'day everyone,

 

I thought I'd share my experience in having the power brake unit from my 1956 Buick rebuilt. As many of you may know, the 1956 Buick power brake unit is a one-year only part (one of many), which makes sourcing parts a challenge; it is even harder in Australia. So, when it came time to rebuilding it, there weren't many options. 

 

I should also mention, I wish to keep my cars as close to original as possible. Yes, the thought of dual-circuit disc brakes has crossed my mind, and the safety in knowing there's a second circuit should one fail is reassuring,  but when making modifications such as those, we have to ask ourselves, "where do we stop?". (No pun intended). 

 

The first option was to have it sent over to the United States; I have read about a place in Calverton, New York, whose name is similar to that of a fruit, and people's experiences seem positive. Of course, the shipping costs would be enormous; the time for it to arrive and be sent back to me would take months; and there is always the possibility of it going missing in transit. But, these are the things we risk. For now, this seemed like the most sensible and feasible option. 

 

I mentioned this plight to a colleague at work. He suggested taking to unit to a place in Campbellfield, in the Northern Suburbs of Melbourne. After four weeks, I have the unit back, and it looks great. It wasn't cheap, costing the best part of $3K, but hopefully the unit will outlast me. I'll post a few pictures so you can judge their work. 

 

I decided to not mention their name here, but, if you'd like to get in touch with them, drop me a line and I'll be happy to pass on their contact information. 

 

Cheers,

Nick 

[lancemb]

Looks great!  I hope it works as well as it looks.

[NickG]

4 hours ago, lancemb said:

Looks great!  I hope it works as well as it looks.

Thanks mate, I hope so too. 

 

Unfortunately I'm having an issue with the pedal bottoming out. The system has been bled, shoes correctly adjusted at all wheels, no leaks that I can see; am I missing something here? 

[EmTee]

Did you have a hard pedal when the brakes were bled?

[NickG]

50 minutes ago, EmTee said:

Did you have a hard pedal when the brakes were bled?

Interestingly, with the engine off the brake pedal is quite firm and it appears to maintain pressure in the system. When the engine is running, the pedal will bottom out. 

 

I can only assume there is an air pocket somewhere in the line, possibly at a high point, and when the engine is running the vacuum assistance helps compress whatever air is in the line. 

 

I will re-bleed the system tomorrow and hopefully the problem disappears. The pedal also needs to be adjusted accordingly

 

Nick 

[JohnD1956]

That system should be able to bleed by gravity. The only possible high point is the rear line over the axle. 

I suggest disconnecting the line at the master cylinder and blocking the port with a suitable plug. Then run your engine and see if you still bottom the pedal, which should then isolate where the problem may exist. 

[NickG]

21 minutes ago, JohnD1956 said:

That system should be able to bleed by gravity. The only possible high point is the rear line over the axle. 

I suggest disconnecting the line at the master cylinder and blocking the port with a suitable plug. Then run your engine and see if you still bottom the pedal, which should then isolate where the problem may exist. 

Thanks John, I'll give that a go tomorrow and report back. I have read on this forum that the '56 seems to be quite a chore to bleed completely

 

Nick  

[PONTIAC1953]

well that is a different version of the Delco Moraine treadle vac type power brakes.

[JohnD1956]

3 hours ago, NickG said:

Thanks John, I'll give that a go tomorrow and report back. I have read on this forum that the '56 seems to be quite a chore to bleed completely

 

Nick  

I don't know why anyone would have a problem bleeding a 56 Buick. Just open a bleeder valve till the fluid runs out and you're done. At least that's how mine worked out. 

[NickG]

9 hours ago, pontiac1953 said:

well that is a different version of the Delco Moraine treadle vac type power brakes.

How so? I was under the impression that 1956 had only one power brake unit

6 hours ago, JohnD1956 said:

I don't know why anyone would have a problem bleeding a 56 Buick. Just open a bleeder valve till the fluid runs out and you're done. At least that's how mine worked out. 

In all my years on working on cars I haven't encountered any trouble bleeding brakes. I know it is unwise to completely rule out the master cylinder as being problematic, but it was only rebuilt last week. I'm going to check each wheel cylinder, as, although unlikely, there at be a leak at one 

[NickG]

Update: The rear passenger-side wheel cylinder is leaking considerably. There was a large puddle of brake fluid on the ground this morning and fluid level in the reservoir has also dropped. I am now convinced the system is free from air and that the cause of poor pedal performance resulted from the leaking wheel cylinder. 

 

Below is the wheel cylinder I received AFTER being sent off for re-sleeving. Notice the considerable scoring on the cylinder wall; the piston is unserviceable and should not have been reused. Safe to say, I will no longer be using their services and will instead order new ones from the States. 

 

I should mention that this a DIFFERENT company than those who rebuilt the master cylinder. So far I am happy with the master cylinder, although it hasn't been road tested. 

 

Nick

[PONTIAC1953]

13 hours ago, NickG said:

How so? I was under the impression that 1956 had only one power brake unit

In all my years on working on cars I haven't encountered any trouble bleeding brakes. I know it is unwise to completely rule out the master cylinder as being problematic, but it was only rebuilt last week. I'm going to check each wheel cylinder, as, although unlikely, there at be a leak at one 

well I said Delco Moraine, I didn't say 1956 Buick, all five brands under General Motors used either the Delco Moraine unit, or the Bendix Treadle Vac unit, or both, from 1952 for Cadillac, Buick, Oldsmobile, from 1954 for Pontiac & Chevy, up to either 1958 or 1959. Pontiac even told dealers to invite 1953 Pontiac owners back to upgrade their 1953 Pontiac with the Treadle Vac with a dealer's field installation kit.

[PONTIAC1953]

I removed this upper remote brake fluid reservoir from a 55 or 56 Buick, to make it much easier to check, add, or bleed brake fluid on the Treadle Vac mounted below the steering column on my 1953 Pontiac Chieftain Custom Catalina. 

[NailheadBob]

2 hours ago, pontiac1953 said:

I removed this upper remote brake fluid reservoir from a 55 or 56 Buick, to make it much easier to check, add, or bleed brake fluid on the Treadle Vac mounted below the steering column on my 1953 Pontiac Chieftain Custom Catalina. 

Friend of mine added the auxiliary brake fluid reservoir to his 1953 Cadillac, and it was listed with illustrations in the 1954 Cadillac master parts lists, BUT I did not find it in the Buick Master Chassis book, maybe I am looking in wrong spot? OR could it be someone added it to the Buick you got it from?

 

Bob

 

 

 

Edited September 25, 2022 by NailheadBob
Add photo (see edit history)

[NickG]

18 hours ago, pontiac1953 said:

well I said Delco Moraine, I didn't say 1956 Buick, all five brands under General Motors used either the Delco Moraine unit, or the Bendix Treadle Vac unit, or both, from 1952 for Cadillac, Buick, Oldsmobile, from 1954 for Pontiac & Chevy, up to either 1958 or 1959. Pontiac even told dealers to invite 1953 Pontiac owners back to upgrade their 1953 Pontiac with the Treadle Vac with a dealer's field installation kit.

I stand corrected, you're right. Thanks for sharing this information. 

18 hours ago, pontiac1953 said:

I removed this upper remote brake fluid reservoir from a 55 or 56 Buick, to make it much easier to check, add, or bleed brake fluid on the Treadle Vac mounted below the steering column on my 1953 Pontiac Chieftain Custom Catalina. 

Looks good, well worth the investment. It would save a lot of hassle. 

 

Generally speaking, what is the reliability of these units from this era? I've read that the model in my Buick appears to be reliable, but there are mixed opinions. With regular brake fluid changes I don't see why it would be inherently unreliable. If anyone can shed some light regarding this, it would be greatly appreciated.

 

Nick 

[spag4203]

I am interested in getting mine rebuilt. Can you share with me the name of the place you sent yours to in NY?

[Frank DuVal]

He did not send it to New York. He used a shop in Australia. 
 

Nick, if you are still around, what was wrong with the piston in your wheel cylinder picture?  I’ve used scored pistons many times as the seal is only the rubber one. The piston just moves and does not seal. Cleaning the cylinder after honing is important. Grit destroys seals. 

[EmTee]

On 3/5/2023 at 7:43 PM, spag4203 said:

Can you share with me the name of the place you sent yours to in NY?

Are you referring to Apple Hydraulics?  http://www.applehydraulics.com/

[spag4203]

Yes, thank you!

[NickG]

On 3/6/2023 at 11:43 AM, spag4203 said:

I am interested in getting mine rebuilt. Can you share with me the name of the place you sent yours to in NY?

Hi mate, I'm in Melbourne, Australia, and was lucky enough to have a local place rebuild my power brake unit. At a last resort, I was condescending the above-mentioned place in New York, Apple Hydraulics. The general consensus is pretty positive regarding their work, but the cost to have it sent from Australia to New York, then to have the work completed, and then back to Australia, would have been outrageous. All the best with your unit. If I can ask, what is wrong with yours? 

 

On 3/7/2023 at 6:54 AM, Frank DuVal said:

He did not send it to New York. He used a shop in Australia. 
 

Nick, if you are still around, what was wrong with the piston in your wheel cylinder picture?  I’ve used scored pistons many times as the seal is only the rubber one. The piston just moves and does not seal. Cleaning the cylinder after honing is important. Grit destroys seals. 

G'day Frank, 

 

Yes, you're right. Luckily enough, the shop was in the same state, too. 

 

At a guess, I'd say that grit was pushed into the wheel cylinder at some point during installation, and that is what caused the scoring of the cylinder wall. 

 

That is a very good point and one I did not consider, but in the end, I replaced all four wheel cylinders, bleed the system, this time with the help of a friend, and it has worked perfectly ever since. For what people say regarding old drum brake systems, I have to say that in my experience, this system has been quite good - now that everything has been freshened up. 

 

The only issue I have is pedal return; it is hit and miss. Most of the time the pedal will return at what I consider a 'normal' speed, but sometimes, usually when cold, the pedal is very slow to return to the rest position. Rarely, I have to assist the pedal in returning. Unfortunately, the springs weren't changed as they were impossible to source here. So, if anyone knows of a place that has the full spring kit (front and rear), then I'd greatly appreciate any help. 

 

[JohnD1956]

The pin that the brake pedal hinges on is adjustable and should be adjusted for just this reason, according to the factory service manual. 

 

Also I used the spring kit for a 63 Buick full size model, which was listed in the NAPA computer. These springs were much more robust than my original spings and thus provide a bit of resistance feeling in the brake pedal, but like yourself, my drum brakes are still very adequate. 

[56Twotone]

I have a '56 Century that recently sat for about 20 years, thankfully the master cylinder only needed to be cleaned and was in excellent condition internally (low mileage car, lifetime dry storage.)

 

What is the consensus on using original, unrestored units? Obviously leather cup seals of a 1955 vintage aren't ideal, but it seems to stop just fine, albeit with relatively firm pressure on the brake. I know the vacuum assist is working at least to some capacity, as the power units are supposed to be even firmer than the manual ones without a good vacuum supply. The parking brake works, so I'm not completely out of luck if something does "let go", but I'd like to know if a hypothetical seal failure would more likely cause a sudden loss of vacuum assist, or a sudden loss of all braking potential entirely... according to what I could glean from the manual, I'd assume the former, but it would be good to know for sure if this is a situation where my life is actually on the line.

 

My suspicion, too, is that a "rebuild" would not actually replace many of the components that I'm concerned with. The last time I was in there, I saw a lot of oddball rubber cups and seals and on and on. I'd be surprised if replacements for those parts exist, and since all the metal in the unit is absolutely pristine, I wonder if I'd be paying God knows how many hundreds for someone to simply throw in a new leather vacuum seal and hit the housing with a paint gun. The car barely gets driven, so I'm not too concerned about it yet, but it's another thing to keep in mind.

[JohnD1956]

Safe or not, it is on your mind as a safety issue. I would recommend contacting the rebuilders to ask about what steps and parts their process includes, so that you can make a decision that restores your faith in the system.  

I did have mine rebuilt in the late 80's because I found it empty with no visible evidence of a leak anywhere other than at the reservoir's connection. But for safety reasons I try to leave a few extra car lengths open ahead of me.  That is not easy in todays driving environment.  However, I feel like I know my Buick will stop when needed, which is a feeling you have not had a chance to develop. And likely won't while worried about 60 year old parts.  And you are justified in your concerns in my opinion. 

[old-tank]

Try THIS.

I would spring for the rebuilt unit, because if you just get a "kit", you will discover other parts that need replacing like the fluid displacement rod, housing...

[David Bouwer]

Hello,

 

Reading this post, I think I have the same issue: the brake pedal does sometimes not return. If I disconnect the vacuum line, the problem is gone. So it has to do with the vacuum. @NickG do you have any progress in your issue? As expected, I am very interested…

[NickG]

On 3/8/2023 at 11:21 PM, JohnD1956 said:

The pin that the brake pedal hinges on is adjustable and should be adjusted for just this reason, according to the factory service manual. 

 

Also I used the spring kit for a 63 Buick full size model, which was listed in the NAPA computer. These springs were much more robust than my original spings and thus provide a bit of resistance feeling in the brake pedal, but like yourself, my drum brakes are still very adequate. 

Thanks mate, I've adjusted the pedal correctly, such that there's no binding. I didn't know the spring kit for the 1963 model worked. I think I'll order that kit for my '56. Is that the front and rear kit? I'm pretty happy with the drum brakes. Thankfully I've never had to perform an emergency stop in the Buick, but I feel that, should it ever be required, it will pull up adequately. 

 

On 3/19/2023 at 2:20 AM, old-tank said:

Try THIS.

I would spring for the rebuilt unit, because if you just get a "kit", you will discover other parts that need replacing like the fluid displacement rod, housing...

Thanks for the site. I've never heard of them before, but will order a few bits and pieces to have here as spare. 

 

13 hours ago, David Bouwer said:

Hello,

 

Reading this post, I think I have the same issue: the brake pedal does sometimes not return. If I disconnect the vacuum line, the problem is gone. So it has to do with the vacuum. @NickG do you have any progress in your issue? As expected, I am very interested…

Hi mate. That's interesting. I ended up centering the shoes and readjusting them. Kept on bleeding them until I was certain the system had been purged of air and haven't had any issues since. 

 

Has your unit been rebuilt or worked on? 

[old-tank]

As a test disconnect the pedal rod boot.  On some if it seals "too good", the pedal will not return.

[David Bouwer]

I have slid the booth a bit back, but I suspect that is not enough. Will try to move even further, but it is very firmly seated….. the booster also hisses a bit. Is that normal? You can hear that through the 2 little holes in the booth, but only once it starts to come back up. Interesting thoughts about the booth sealing to much. As it does seem to come up normally if I wiggle the booth by hand