Jump to content

Recommended Posts

So as you might see over in "buick crashes" I had a mishap this weekend.  I was out riding when at one stop light, after stopping, the pedal went down while holding it. I immediately pulled my foot back and pumped the brakes a bit and it held while stopped. So I headed home pumping the brakes each time I stopped.  The pedal didn't hit the floor again.  I got home and D*mn.... Pedal to the floor and kissed the garage.  Garage is "fixed" and only one scratch on the car's front bumper.

Tonight I decided to start inspecting as the car was sold with "new brakes".  Pedal feels firm again, fluid level appeared normal, drums, shoes, wheel cylinders, and lines are all clearly new. No evidence of leaks anywhere. Could it just be air in the lines from improper bleeding or a faulty master cylinder?

 

Also. Check out these front drums... Not stock

20210315_185919.jpg

20210315_190002.jpg

Edited by NC-car-guy (see edit history)
  • Like 1
Link to post
Share on other sites

With the way you describe the failure and the fact that there is no fluid loss, it points to the master cylinder having a failure. I am not familiar with your specific brake system so I can not offer any specific places to look. I would remove and disassemble the master cylinder and carefully make note of exactly how it was assembled. Then I would closely inspect the cylinder bore and the rubber cups for any damage. Assuming all looks good, then I would do my best to find a factory exploded view of the cylinder assembly and compare how it was assembled. That is all I have. I remember a post somewhere in the forums where a master cylinder failure was traced to some internal part installed backwards. I hope this gives you a direction to investigate.  I am VERY glad that you or anyone else were not hurt and the garage and car only had minor damage.  Be safe!!

  • Like 2
  • Thanks 1
Link to post
Share on other sites

Power brakes?

 

8 minutes ago, avgwarhawk said:

Master cylinder issue.

 

That's what it took to get mine right. Glad you and the car didn't end up in someones back seat.

  • Like 1
Link to post
Share on other sites

I believe I have one last 1957 Buick With Manual Brakes Master Cylinder..... That is a one year Only / Manual Brakes Only Master Cylinder...

... Those are the Chineseum reproductions Brake Drums --- I have four (4) remaining N.O.S. O.E.M. G.M. Brake Drums if you would be interested in U.S.A. made !!!!!!

    Always best to simply call me --- Craig --- 516 - 485 - 1935.... 

New York....

Edited by mobileparts (see edit history)
Link to post
Share on other sites
1 minute ago, mobileparts said:

I believe I have one last 1957 Buick With Manual Brakes Master Cylinder..... That is a one year Only / Manual Brakes Only Master Cylinder...

... Those are the Chineseum reproductions Brake Drums --- I have four (4) remaining N.O.S. O.E.M. G.M. Brake Drums if you would be interested in U.S.A. made !!!!!!

    Always best to simply call me --- Craig --- 516 - 485 - 1935.... 

New York....

The drums are new.  I'll run them till I can't. I'm not concerned with originality and once I have enough saved up I plan to upgrade.  Looking for a rebuild kit for my master now to hold it over.

Link to post
Share on other sites

That is weird.  There is not a lot to go wrong in a standard master cylinder.  Could be a failing cup seal that is intermittently distorting.  Rebuild kits are plentiful for these.

  • Like 3
Link to post
Share on other sites
2 hours ago, NC-car-guy said:

I've order the MC rebuild kit and of course some wheel alignment pins for the rear drums... I was cussin' putting those wheels back on. 😁

Make some studs (2) to help even with pins...absolutely necessary with wire wheels.

  • Like 1
Link to post
Share on other sites

It looks like two bolts are holding the brake drum on. One of those should be a locating pin. It wouldn't be hard to make one.

 

Check your drum inner diameter and the mounted shoe outside diameter. There is a chance components may be traveling beyond their normal range or not traveling enough.

Always expect the unexpected. I would check to make sure the wheel cylinder manufacturer drilled out the fluid passage on all four cylinders and the brake tube junction blocks. But I don't trust anything.

Link to post
Share on other sites
6 minutes ago, avgwarhawk said:

This will  allow you lift and spin the tire as you locate the lug nut holes or the studs themselves depending on what you are working on.

 

  BW-CJD.jpg?v=100114417026-2

Not a bad idea

Link to post
Share on other sites
12 hours ago, avgwarhawk said:

This will  allow you lift and spin the tire as you locate the lug nut holes or the studs themselves depending on what you are working on.

 

  BW-CJD.jpg?v=100114417026-2

 

That is cheating!!   Oh well, I never said I played fair 😇.

Link to post
Share on other sites
On 3/15/2021 at 11:36 PM, lancemb said:

That is weird. 

No, normal failure! The inner seal wears and the hydraulic fluid bypasses internally instead of building pressure in the output port. The only other way a master cylinder fails is leaking out the actuating pin end.

 

The failure is noticeable first as the pedal goes to the floor with light brake application, but works great when stomped on, as the seal then is tight. This makes the master seem too be fine. It will get worse, I kept putting off repair on my 66 Chevy wagon to where you had to continually apply the brakes at a stop light! Young and stupid... Rebuilt it that day...😲

  • Like 2
Link to post
Share on other sites
36 minutes ago, Frank DuVal said:

No, normal failure! The inner seal wears and the hydraulic fluid bypasses internally instead of building pressure in the output port. The only other way a master cylinder fails is leaking out the actuating pin end.

 

The failure is noticeable first as the pedal goes to the floor with light brake application, but works great when stomped on, as the seal then is tight. This makes the master seem too be fine. It will get worse, I kept putting off repair on my 66 Chevy wagon to where you had to continually apply the brakes at a stop light! Young and stupid... Rebuilt it that day...😲

I must be a very unlucky guy.  I've had 2 fail, and it was pretty sudden both times.  Luckily, I'm still here to reminisce.

  • Like 2
Link to post
Share on other sites

Manual brakes I would definitely rebuild the master.  It's a different type of setup than the power brake system on these cars.

 

Funny, people think the drum brakes on these cars are inferior to disc brakes.  On any of the cars I've had with a properly working system will stop as well as any of the modern systems.  The 57 Roadmaster I had last year was an anomaly with its system.  I couldn't figure out why I had a terrible pedal feel, and it ended up being anchor pin adjustments.  After that, the brakes were awesome again. 

Edited by Smartin (see edit history)
  • Like 7
  • Thanks 2
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...