1952 Buick brakes

[krinkov58]

While on a drive a week or so back, my Roadmaster's brakes felt REALLY mushy but at the time the engine was sputtering/dying and my main focus was getting the thing home and avoiding a tow (I was right around the corner from my house).  So testing today it's apparent that the brakes are not doing a whole lot all of a sudden.  The pedal sinks right to the mat before anything happens whereas previously they worked perfectly.  

Before I purchased the car in January, the previous owner had brake work done at the end of July 2014.  All of the receipts came with the car...he bought a new master cylinder, 4 new wheel cylinders, a brake hardware kit, new brake shoes and hoses from Kanter. These were installed by an auto repair place in Mechanicsburg PA and all the drums were turned, brake system was bled and adjusted and road tested on 7/24/14.  The previous owner then placed the vehicle in a storage facility shortly after, sold it to me and I had it picked up from the same storage facility.  I have driven the car MAYBE 40 miles since January.  

Tomorrow I'm getting under the car to check things out...anything in particular I should be looking for?

[SpecialEducation]

There's nothing too exotic about these old brake systems.  Obviously, locating wetness is going to be a primary concern.  It sounds like you developed a leak somewhere and have pumped all of the fluid out of your reservoir and now you are pumping air into the system.  It could be a very small leak that makes no noticeable effect on system performance for quite some time, but once the fluid level in the system got low enough to draw in air, the brakes went mushy and you were done.  

 

Now, if you pop the hood and find the reservoir is still full, we've got a different problem...

Edited September 17, 2015 by SpecialEducation (see edit history)

[avgwarhawk]

I'm believing the master cylinder has failed. 

[Pete Phillips]

I would also be suspicious of the "new master cylinder" as Chris says. I don't think you can buy new master cylinders for these cars--just rebuild kits is all I've ever found. If it was really a new one, was it 60 years old on the shelf, in which case the rubber seals inside it may have failed?

Pete Phillips, BCA #7338

1948 model 56-S

1948 model 76-S

1949 model 51

1949 model 59

and other Buicks...

[SpecialEducation]

Well, yes, if there plenty of fluid but no pressure to the wheels, a master cylinder failure would be that 'different problem..."  I was just trying to be optimistic!

 

By the way, a few years back we had our master cylinder/booster rebuilt by Ed Strain down in Florida.  Anyone else use him?  What kind of experience did you have?  Ours still isn't quite right; not sure if we'll send it south for the winter, or go a different route.

[Bhigdog]

Well......... Ed is not expensive and turns the units around pretty quick. I can relate an experience I had with my 57 booster he rebuilt. When it came back the booster worked but the pedal would not return for a few seconds after applying the brakes and the brakes would stay applied until it returned. Very aggravating. I called Ed and he said the unit bench tested OK. He said I needed an external return spring (it didn't came with one from the factory). I rigged one and it did no good. I sent the unit back. Ed sent it back with a note saying it bench tested good. I reinstalled it and it was still the same delayed return. I called Ed and he said it bench tested good. So that was that. Loooong story short, after much dicking around and several days labor removing disassembling, removing disassembling, and much reading of shop manual booster theory of operation I came to the conclusion that the small vacuum valve return spring was weak. I simply stretched the spring a bit and the problem was solved.
There is a small vent hole with a cleaning wire drilled in the master cylinder bottom between the piston rod seals to vent that area to ambient pressure and prevent system vacuum from drawing brake fluid back into the canister. For some reason Ed removed the wire and plugged the vent hole with silicone sealant. I cleaned out the sealer and made/installed a new wire.
After the fixes the unit continues to operate fine with no external return spring required.
I am casting no aspersions on Ed's work but am only reporting my experience. Others may have had satisfactory results.................Bob

Edited September 17, 2015 by Bhigdog (see edit history)

[trp3141592]

Hi,

 

I have had success with cylinder sleeving and rebuilding at brakeplace.com.

 

I also wonder if the guy who did he brake work used compression fittings rather than flare fittings for any brake lines that he replaced.  That's a major no-no, and if so, you'll see fluid at brake line unions.

 

--Tom

[krinkov58]

Pete, it was a rebuilt unit from Kanter, still under warranty:  https://www.kanter.com/productdetail.aspx?DeptNo=1100&MakeName=Buick&MakeYear=1952&CategoryID=54&ProductCode=233&Router=Catalog

 

So I backed the car out of the garage and took some pics, wasn't hard to figure out that the rear passenger line was leaking from the nut.  There was a small puddle of brake fluid inside where the tire was parked and brake fluid running down the back of the tire.  Master cylinder was pretty low.  Small leak but over time I am pretty sure air eventually got in just as suggested.  The nut wasn't terribly loose but not terribly tight either.  Sigh....time to bleed....

 

Thanks all for your replies!

Edited September 18, 2015 by krinkov58 (see edit history)

[SpecialEducation]

Well, fluid is cheaper than a master cylinder, and either way you'd have to bleed it, so call it a win!

 

Bhigdog, your symptoms sound a bit familiar.  Occasionally the pedal doesn't make a full return.  I can tell when it doesn't come back, because I hear the vacuum booster hissing.  A quick tap usually frees it up; but I don't think I've had to lift it with my toe since the rebuild.

[Bhigdog]

That sounds a bit different but could be related. Possibly the vacuum piston is not being returned all the way because the can is a bit dry or the cup seal is a bit on the tight side. A 1/2 ounce or so of ATF poured into the breather might help but most likely won't..........Bob

[David Childs]

Well, yes, if there plenty of fluid but no pressure to the wheels, a master cylinder failure would be that 'different problem..."  I was just trying to be optimistic!

 

By the way, a few years back we had our master cylinder/booster rebuilt by Ed Strain down in Florida.  Anyone else use him?  What kind of experience did you have?  Ours still isn't quite right; not sure if we'll send it south for the winter, or go a different route.

Here is my input on the guy in Florida.  I used him years ago to rebuild my '54 Packard brake booster and it was a job well done.  More recently I used him to rebuild the master cylinder and power booster on my 58 Buick Super.  When the unit came back there was still a problem with fluid getting into the vacuum chamber.  I sent it back to Florida at "his" request and he checked it again.  It got back to me the 2nd time still not working like a power booster should PLUS it has a sizable dent (like an egg) in the side of the vacuum chamber due to mishandling by UP? you-know-who.  Then I read in the forum about White Post Restorations and another brake booster restorer and decided that I would use someone like them if the 58 power booster ever came off the car again.  NO MATTER what the cost.  I drive my 58 Super using old advice given long ago--leave plenty of room to stop and a bit more to take off.

Edited September 28, 2015 by David Childs (see edit history)

[60FlatTop]

I have some neat stuff in the brake drawer of one of my tool boxes. There are a handful of short sections of line with fittings and the tubing soldered closed. I use those for the untenable jobs where I need to isolate the master cylinder, wheel cylinders, or hose connected line sections. That way I can establish a hard pedal from the master cylinder outward.

I have  real drum pullers of both types.

And I have a master cylinder cap with the vent hole soldered closed and a 3/8" pipe nipple out the top for reaching those pesky GM master cylinders under the steering column with Tygon tubing.  It is all stuff you buy and make as you go along. I can isolate and build a firm pedal on a master cylinder in about 20 minutes.

 

Pulling the pedal up with a hand or toe makes me wonder how old the brake return springs are. It can also indicate lots of brown mucky rust in the wheel cylinder. Peeling back a couple of wheel cylinder boots usually confirms that.

 

If there is rust in the brake fluid water has been lying in the low spots and eating the inner diameter of the steel lines. I check those by gently squeezing the sides of the line with vise grips, just a half turn at a time. If they are thin the bottom cracks open like a lobster shell.

 

It's a system and all the components function together. Check it all and don't worry about breaking something. If it breaks it was probably ready to.

Bernie

Edited September 29, 2015 by 60FlatTop (see edit history)