Hi guys. My brakes in the moredoor are sometimes going right to the floor but if i give it a quick pump they hold. I believe its the master cylinder. I have the power assisted brake booster on this car. Does anyone know if my master cylinder would be the regular style or a heavy duty model? I have the two options and want to make sure I order the right one.
Your master cylinder appears to be regular production, upgrade would be metallic pads which would have come with a bolt thru the cap instead of the spring clip. This informed mechanics that the car was factory equiped with the metallic pads.
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pontiax- (canadian pontiac X frame)1964 Parisienne 2dr. Hardtop ,lagoon aqua metallic (Q) ,421 cid Dart Industries block and heads. 550 hp. 575 ft lb of torque.
now is the time to "upgrade' to a dual master cyl. set up for safety!!!! Think a 68 to 70 chevelle with drum brakes would be the ticket, a proportioning valve off same car & run a new lines!!! Much safer than a single.
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Some times I wake up GRUMPY, but today I let her sleep in !!!!!!!!BLACKSTOCK Ont.
although an upgrade to a dual system is the wise thing to do ...personally I would correct the
issue of a low pedal first....sounds like a brake-shoe adjustment is in order....make sure the e-brake is
backed off...then bleed the brakes (furthest to shortest wheel cylinder) if the pedal issue is not corrected
.....then switch to the dual system
had this problem with my Avanti, was a internal "leak' in M/Cyl.!!! Changed the Master, & had a firm pedal!!! It; used to slowly sink to the floor at a stop light, quick pump brought it back firm but would sink again!!! hardest part was figuring out what M/cyl. to order, turned out to be a 68/69 "FORD" Torino ????
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Some times I wake up GRUMPY, but today I let her sleep in !!!!!!!!BLACKSTOCK Ont.
had this problem with my Avanti, was a internal "leak' in M/Cyl.!!! Changed the Master, & had a firm pedal!!! It; used to slowly sink to the floor at a stop light, quick pump brought it back firm but would sink again!!! hardest part was figuring out what M/cyl. to order, turned out to be a 68/69 "FORD" Torino ????
thats exactly what mine is doing intermittently.
I really want to take the czr to the last show of the yer wit my dad but too afraid it might just let go..............................................
You are right, it's not safe to drive it like that. Best to get a rebuilt master cylinder and get it changed as soon as a you can. It should be readily available at most auto parts stores.
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars
Blow a whl. cyl. or a brake line & you'll wish you had changed over to 'dual' system!!! & by the way it's not a "emergency brake" but a "parking" brake!!! Not meant or designed to be used for stopping car in motion!!!! I'm taking above answer as "JOKE" & hope "MoboMac is tongue in cheek??? When the pedal hits the floor & your heart is in your mouth, it's TOO LATE!!!
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Some times I wake up GRUMPY, but today I let her sleep in !!!!!!!!BLACKSTOCK Ont.
Best to throw that master cylinder in the garbage. Take the booster and get it checked, a lot of times the diaphragm is damaged. The last brake system I changed up was on my convert and it was a mid to late 60's dual master I bought and I got a proportioning valve from the same era WITH ALL THE FITTINGS as they are different from standard fittings both on the master and valve. You also have to get the right bore, there is a shallow and deeper bore on the cylinders to match up with the push rod on the booster. You may have to adjust or change the rod on the booster for the cylinder. From the master two lines go down to the valve which you mount on the frame and three come out, one to the front left, one to the front right and the other to the back rear end. IF the brake lines are good on the car run a short new line to the front left, a new line over to the front right and a new larger line over to the passenger side and use a connector to tie into the line to the back. If you can find someone with a hydraulic brake flare tool trust me you will not be redoing the lines over and over to get them to seal. I bought a 25' coil of the easy bend brake lines, got both ends flared and then cut the lines to lengths and took then back and had them flared until I had them all done - no leaks. I gravity bled the system and I have power brakes that stop dead. This is the least expensive way to get a great brake system on an older Pontiac or Chev. A lot of guys go with the disc brake setup but a good dual master cylinder with drums works great. Also the disc brakes actually move the wheel outward which could be a problem on your project.
Just to add to my post- get a master with drum front and back, some cars of that era did come with disc front and drum back- unless you are going with a disc brake conversion.
Just to add to my post- get a master with drum front and back, some cars of that era did come with disc front and drum back- unless you are going with a disc brake conversion.
Thanks to everyone for all the input. I ended up buying a replacement master cylinder from my local parts depot. Its an identical match, made very well (in Italy!) and is functioning as new again. When I removed old master I found it was leaking at the little diaphragm and seal. It actually took me all of 40 minutes to perform the change and I didnt even need to bleed the brakes after as I was careful on how I removed/reinstalled the lines.
I may do a conversion down the road but this was an efficient and roadworthy fix for now. My next big investment is going to be dual exhaust.
