52 Custom - Brake Bleeding PTSD

[Justin Pease]

Hello again! A brief hiatus from the forums as I spent hours and hours underneath the car every evening after work. Things that are new, for those that are probably not that interested:

 

-New fuel tank

-New fuel lines (this was a nightmare. I had to empty the tank twice, and I earned chemical burns on both of my arms from 93 non-ethanol. Ow.)

-New distributor cap

-Windshield chip filled (thanks to the guys at the local glass shop, and they thought the car was so cool they did it for free!)

-And a lot of driving! Put about 500 miles on the car since my last post, and it's running very well. It was my daily for about a week straight, through rain and shine.

 

My next problem is this. I had been running the car on 3 brakes (the left front wheel cylinder was totally shot - bleeder screw snapped of inside it and so did the screw extractor. Whoa). I finally got round to installing a new wheel cylinder on that side to find that once my brakes were bled, the left front was completely locked from going forward (backwards was fine). I spent at least 5-6 hours total (across a few days) bleeding this brake system to get a nice firm pedal. Further investigation revealed I had a brake lining that was delaminating from the shoe. Yesterday, I replaced those shoes and the problem was solved - except that my pedal still goes to the floor. I can't believe I still have air hiding in the lines - I've put 4-5qts of brake fluid into this car and pumped it out across all the wheels (mostly the fronts). I originally followed the order (furthest first, according to the manual) but eventually I just started going round and bleeding each one that I suspected in no particular order at all.

 

I've now bled the brakes on this car on 8 separate occasions, and I think if I ever see another bleeder screw again I might curl into the fetal position and slowly rock back and fort while muttering about "brake lines" and "bleeder screws" and "3/8, no no, 5/16 on this one." I thought I solved the bleeding issue yesterday (I finished on the backs, inverse of the proper order) and got no bubbles from my lines.  But when I took the car for a jaunt, I had a lack of stopping power, enough to come to a quicker (but not quite a short) stop, but not enough that wheels locked. Pumping the brake pedal did produce this effect, after 3-4 pumps. By the time I got home, my pedal was going all the way to the floor and I had to pump it a few times to get it to stop anytime this year.

 

Is this air leaking into my lines somewhere? Is my master bad? Is it possible that air is sneaking in around the bleed screw threads? I've had various people pumping my brake pedal, and they all agree by the end of the bleed process that the pedal is firm the first pump. By the time I get back from a 2mi drive, the pedal is soft again and stopping is a suggestion, not a command.

 

Anyone have this happen before? Any good ideas on how to solve it? Is it worth it to just bring the damned thing to a shop and make them bleed the brakes since I might go crazy if I have to do any more?

 

Thanks y'all.

[61polara]

I think you need to adjust the brakes.  I'd recommend doing the full adjustment procedure outlined in the shop manual.  When I bought my 1950 Windsor, you had to pump the pedal twice to get brakes.  Seller said that the brakes needed to be bled, not so.  A quick adjustment of the brakes from the backing plates got me a good pedal.  I'll do the major adjustment when I go through the brakes completely.

[c49er]

Did you make sure the brake shoe linings match the drum curve exactly?

If not the new shoes need to be arced to fit each drum.

Then as mentioned the major brake adjustment is necessary.

Go to the p15/d24 site for more info.

Use the factory shop manual too for tech info on Lockheed fixed anchor brakes.

[Joe Cocuzza]

Here's the link to the P15-D24 procedure:

https://p15-d24.com/page/p15d24/tech/brakes.html/

[keithb7]

When the shoes are out of adjustment pretty bad the amount of travel from when you push the brake pedal at the master, its not enough to push the cylinder out far enough to make the shoes reach the drums.

You need a way to set the shoes up concentric to the axle centre, and very close out to the drums.  You may be interested in the tool I fabricate and sell. If you have an interest, let me know.

 

You can see it in action here:

 

 

 

 

 

 

[auburnseeker]

I just finished up the brakes in my 51 Dodge roadster and it was a PIA.  Even with the right tool.  I just bought one of these i stumbled across on ebay.  Even though I checked the shoes and they looked properly arced when checked to the drum,  the gauge showed they were still off.  When checking with feeler gauges at .006 and .007 things showed up you wouldn't see without doing it this way.  I have never used the tool before but with all the Major adjustments in the drum and being Blind you really need that tool.  Though you can sometimes get away with aligning the arrows,  a couple of mine took nearly a 1/4 turn to get the adjustment "right".   I would suggest as mentioned finding the Amoco Miller or the Frisz tool I found or buying the tool keithb7 has.

 

The beauty with the tool i scored,  though I haven't seen another,  is it has self adjusting spring loaded jaws so you slide it on turn the big nut on the front and everything self adjusts to fit the spindle or axle.  No bushings or sleeves like the Miller tool.   It still took forever with the tool,  maybe more than just guessing but I think I have the best brake job possible now. 

 

Good luck.  You will get it,  just when you are about ready to have another episode the stars will align and you will be able to step back and there you X%#*&@ finished.

 

Not that that's what I did.  

Edited August 12, 2020 by auburnseeker (see edit history)

[Justin Pease]

Hey all!

 

I really appreciate all the support on this thread - you guys truly come through every time!

 

Somehow I didn't get subscribed to this thread automagically which means I just read all of the replies here moments ago rather than as they came in. I ended up doing some more diagnosis and bleeding and found that my pedal was decently firm at the end of the bleed job and stayed as such, but within 2 miles of driving, the brakes faded to an unreasonable level and the car came to quite the leisurely stop. Pumping the brakes still caused a better effect, but I couldn't believe that there was still natural air in the lines. I inspected the master cylinder further and found that there was a small, nearly invisible tear in the boot. I wasn't sure that this was the cause, as I didn't think a small tear in this boot could cause the effect I was experiencing, but in the end I was faced with taking her to a shop (I couldn't stand to look at the bleed screws another time without expecting a different result) or replacing the master cylinder. I decided to pursue the BMW Service Advisor method and Diagnose By Replacement^® and replaced the master cylinder.

 

Finished that install today, after also running a new line to the rear (since the old one wouldn't come off without a fight) and upon bleeding all the brakes one last time, I had an incredibly firm pedal, so firm that I had to get used to how high my knee was during braking. The car now stops smoothly, evenly, and (if necessary) quite quickly. My friend and I tested the brakes and had a bit of an incident - we braced ourselves for the lurch of a sudden stop, and suddenly stop we did, but we forgot to brace the unsecured fire extinguisher on the seat, and it viciously attacked my friend's leg with its sharp nozzle. But, foresight shortcomings aside, all is now well.

 

Again, really appreciate everyone's ideas! Keith, I have bookmarked your comment and may return to you in the future to snip up one of them fancy tools: I manually measured the distances with a tape measure and some mathematics, but it took ages and eventually I entered entirely the "guesstimate" method and snipped it all back together.

 

On to the next - I finished this job and returned home, literally 10 minutes after the completion of the brake job, and discovered that I could not open my LR door. Another hour of fiddling and grease, and I've found the problem - but that's the next thread

[c49er]

So your master cylinder was not new or rebuilt and possibly had a torn cup caused by pushing the piston and cup too deep I to the pitted sludgy part of thecylinder....?

That is very common...

On modern cars doing a pad and rotor replacement never push the pedal farther than normal when doing a pedal bleed.

Otherwise a piston cup in the M/cylinder might get torn.

Result endless bleeding till the cows come home.😄