1949 brakes have me stumped!

Steve Miller · October 09, 2011, 12:19:05 PM

1949 Cadillac 60S, had no brakes when I got it and the MC was bone dry. Checked each wheel and planned on putting on new shoes and hardware, but shoes look good and hardware/WC appear to have been replaced recently. No leaks in hoses. Rebuilt MC with a kit, and replaced one line to the front. Bled all the cylinders with vacuum, got some air. Back bled to the cylinder and could hear the fluid coming out of it, still no petal. Have repeated the above 3 times, still no petal at all. Not really interested in converting to power brakes, or dual MC.
Any ideas, replace the MC completely? Any suggestions appreciated.
Thanks

1937 LaSalle coupe · October 09, 2011, 01:40:44 PM

Hello Steve. What I would do, would be to bleed the master cylinder seperate from the brake system. Disconnect the line to MC and hook up a short section of brake line. Have it bend so it will return brake fluid back to the top of the MC. Make sure line is well below brake fluid. Disconnect the line and reinstall the original line and rebleed system again. Should work.... Good luck... John Lehman... CLC # 26365....

TJ Hopland · October 10, 2011, 08:33:07 AM

Was the system dry because someone had been working on it and never finished? OR had it just been sitting that long? Or was it due to a failure in the system? Often times when a system sits open without someone flushing it the lines will get a pretty nasty rust build up internally. This rust weakens the line and can work its way into various places in the system and cause intermittent problems. What condition was the mc in when you started? Lots of rust? Did you have to use a hone? Are you sure its the correct MC and you are getting full pedal travel and most importantly is it able to fully return to the rest position?

Steve Passmore · October 10, 2011, 08:51:29 AM

Something defiantly wrong in the master cylinder there, after all, theres nothing else to go wrong really if its got fluid and it isn't leaking.

Steve Miller · October 10, 2011, 11:46:05 AM

I bought it from a guy in Missouri, who's Dad owned it and died 2 years ago so I think it had been sitting for a while. It looked like the fluid had leaked out around the back of the MC as it had some fluid around that area. When I put the kit in there wasn't any pitting so I didn't hone it out, the cups felt tight going in. It appears to be the original MC, and looks correct based on the manuals I have. I'm going to take it off and try bench bleeding it, if that doesn't work I guess I'll try a new one.
Thanks

kkarrer · October 10, 2011, 04:50:04 PM

Bench bleed that MC first or you'll never get anywhere. Replace it and bleed the system starting with the wheel cylinder that is farthest from the MC and then work towards it. If you still have a problem get a newly rebuilt MC. They're not expensive and they're readily available.
Ken 41 6229D coupe

Caddy Wizard · October 10, 2011, 06:06:32 PM

Definitely bench bleed the MC or you are wasting your time. Replace ALL of the metal lines or take your life in your hands -- see my post at http://www.cadillaclasalleclub.org/forum/technical-authenticity/1956-cadillac-coupe-deville-brakes-decisions-decisions/msg180191/#msg180191

Art Gardner

Steve Miller · October 11, 2011, 03:15:10 PM

Thanks for all the help and suggestions. I am just going to put a new MC on, bench bleed it first, and install new lines/hoses. Hopefully this will take care of it, not worth taking a chance on a 60 year old brake set up.
Thanks again

Len Sholes · October 16, 2011, 01:50:18 PM

Steve, re your brake problem, did you slack of all the wheel cylinders when you had the drums off. If so and you did not adjust them when you reinsatlled the drums it is possible that this could be your problem. If the pedal stays solid when you bleed them it tells me that the hydraulic end of the system is ok and it might just be that all you need to do is adjsut the shoes closer to the drums. I have run across this before.

Steve Miller · October 16, 2011, 04:40:51 PM

Quote from: Len Sholes on October 16, 2011, 01:50:18 PM
Steve, re your brake problem, did you slack of all the wheel cylinders when you had the drums off. If so and you did not adjust them when you reinsatlled the drums it is possible that this could be your problem. If the pedal stays solid when you bleed them it tells me that the hydraulic end of the system is ok and it might just be that all you need to do is adjsut the shoes closer to the drums. I have run across this before.

Nope didn't do anything like that but I'll remember it, once I get the lines all switched out and bled
Thanks

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1949 brakes have me stumped!