help me with the obvious pls

wbedwards

wbedwards

Senior Member
'59 Edsel standard NO power brakes. Since I have had the car, the brakes and brake lights apply themselves when it gets hot. The previous owner put new front lines, new shoes, new slaves. I flushed the lines, replaced rear soft line and rebuilt the original master cyl. I can hear/see the slaves working. I've adjusted pedal rod as far as it will go. I can drive it while its cool and it feels normal, but when it gets hot pedal gets real stiff and brakes come on.
I can run a heat gun on the master Cyl and the brakes and brake light will come on. How can you put new parts in a master cyl. and it still do that? :confused:
Only fix is another master cyl.?

thanks for your thoughts
 
=]
54vicky asked me several questions that made me think about when I rebuilt the MC. I remember there being one port and what looked like one partially drilled hole I was not sure of the function. I cleaned it all up and put it together not pursuing it. I now believe it to be the relief port that is clogged up so bad it looked solid from the cylinder side. I am going to try to punch it through or even hand drill it. I have got to figure out what size it should be. I feel dumb now not pursuing it and have spent days trying to figure this out. I can't try to fix it until this weekend either.

thanks for reading
 
While I'm sure you've got it, I'm going to offer another example. Happened to me. Some MC's are used on both power and non power brakes. And sometimes there's a spacer in the box, used only for the power application. Put that in on manual brakes and you run out of adjustment on the pedal. I did that on a hydro boost unit. Different than the usual vacumn booster. Had what seemed like enough free play, but 15 miles later the brakes went on. With the booster, they really went on. So, while its apart, check.
 
I was not trying to be secretive I made a couple of suggestions as to what the problem may have been.I am sure if they solve the problem he will post the findings.
 
I know what it is, but don't want to interfere upon the course of action. Lawn chair, cold beer, sit back and enjoy the show.
 
Well.... do you concur bobss396? That's why I posted here, because there are many here that know a good bit more than I do on restoring old cars. I've tried since I've been on the forum to share what little I know on car repair. =]
 
I would shorten the rod out of the master by 2 turns to start. Take it for a ride and see what happens. It should be easy to do at the pedal clevis.
 
bobss396 said:
I know what it is, but don't want to interfere upon the course of action. Lawn chair, cold beer, sit back and enjoy the show.
Click to expand...
you forgot hotdogs or popcorn:DI touched on the rod as one possibility but I felt the port was plugged or cup on plunger blocking relief port(my name for it)which would cause the piston not retracting enough to clear allowing pressure to release.did not mean as I said I did not intend to start a shyt storm when he felt rod had slack I mentioned the port being blocked to which he replied he felt that may be the case.now all reading have to swear to the ancient oath of secrecy on peril of take your pick.we also talked about it being wrong master that is the whole truth and nothing but the truth I think
 
Make sure you have some free play in the master cylinder rod. If the piston in the master cylinder does not completely return all the way back in the bore, you will have the problems you described.
 
I backed off the rod as far as it would go. Brakes felt real good until you used them a few times then got all tight. I'm 99% sure its the port, but can't fix till this weekend.

thanks again for your input,
will advise by Sunday night =]
 
Have to agree with my fellow Canadian ;-) If that port is plugged, the brake fluid can't get back into the reservoir when it heats up, and expands.
 
Thanks 54vicky! SUCCESS! It was the (port) hole. I only had an .035 bit or an .045 so I used the .035 and hand drilled it, may be a little small, but it works! I have been chasing this phantom for 3 months. You guys are GREAT and I really appreciate your suggestions.

wbedwards
 
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