58 SDV: Brake issue (Delco)

[wbdeford]

update: Booster is completely disassembled, except the push rod is still connected to the air valve (manual says you don't have to take that apart unless it is loose or noisy).  All booster parts look to be in good shape.  Cleaned everything in alcohol as the manual directs.  Ordered tool J-5794, so will disassemble the master cylinder when that arrives.

[wbdeford]

Anyone have a parts diagram of the '58 Delco master cylinder?  The '58 shop manual supplement mentions a spacer that was not in mine.  It only has a picture of the end plug parts and not the whole MC.

[J. Gomez]

William,

I do not have one specific for the 1958, maybe the generic one that came with a rebuilt kit can be of help.

I’m having difficulties attaching the file for some reason, send me a PM with your email and I’ll be glad to send you a copy. 

Good luck..!

[wbdeford]

Thanks....PM'd you my email.  The '58 system seems to be unique.  I have '57 and '59 manuals and little seems the same

[J. Gomez]

Thanks....PM'd you my email.  The '58 system seems to be unique.  I have '57 and '59 manuals and little seems the same

File send..!

[wbdeford]

Update: booster and master rebuild are complete and reinstalled on the car.  I bled the master cylinder with it on the car (the only procedure given in the shop manual).  Should I expect very much air to have gotten in the main line while bleeding the master?

[Jon S]

Yes. You will need to bleed all of the wheel cylinders starting with the right rear

[wbdeford]

I know I need to bleed them--just wondering how much air to expect--just a little because it disconnects from the master at the high point, so little air gets in?  Or a lot because bleeding the master puts a lot of air into the lines?

One reason I ask this is that I will be pulling the car out of the garage to bleed the wheels and want to know how diminished I should expect the brakes to be.

[Jon S]

If you did not bench bleed the master first there will be at least 3 cycles per wheel cylinder (pump/open/depress/close). Maybe you will be lucky and experience less.

[wbdeford]

I am planning to use a quart of brake fluid and flush out the lines completely.  Sounds like I should expect very little braking power when I pull out of the garage....

[Jon S]

Agreed. Hope your parking brake works well. Also wait for the idle to slow down before moving the car. Good Luck!

[wbdeford]

It's actually a good thing....if you said the pedal should be mostly firm already, I'd be worried, cause it ain't now   Fortunately, my driveway is very friendly for this....yes, definitely will wait for slow idle.

[wbdeford]

Bled the brakes and got a firm pedal....but the power brakes were only partially working.  I thought perhaps the hose inside the booster was collapsing, so I replaced that....seemed to have a slight improvement, but still not much better than manual brakes.  Went back to my pictures and realized I put the reaction plate on backward.  I can't imagine how I did something so dumb, but that's exactly what I did.  Disassembled the booster, partially disassembled the piston, and turned the reaction plate around like it is supposed to be.  Put all back together and re-bled the master. "voila"....the brakes work perfectly once again.

Good news about this is, I am now very efficient at removing and replacing the power brake assembly.  Can take it off the car in about 5 minutes.  A little longer going back on.