Mhegel

i need some help with the brakes on my 67. recently replaced the master cylinder and now today after driving 6 miles home from work the left rear brake was so hot it was smoking. the car has manual drum brakes and im not sure how to proceed with fixing this issue. please help.

Mhegel

also the brakes felt like they were starting to stick about half way home

67mustang302

Inspect them, make sure the pistons aren't stuck, and the hardware is returning the shoes back to resting position. Probably burnt up the shoes on that 1 side though.

bop11

Since only the rear on one side was hot, it sounds like the self adjusters are not acting correctly. The dual brake system ( i think 67 was when they went to dual circuits) splits front and rear not left front right rear and right front left rear. Self adjusters were always a pain in the A back in the 60's. Pull the drum and free up the lever insuring that both springs are properly functioning.

Mhegel

Turns out that the cable for the parking brake came off the pulley wheel under the dash and got wedged between the bracket and the pulley wheel and had just enough tension to put a little bit of pressure on the rear brakes and caused the heat.

Mhegel

so the issue with the brakes sticking is not the parking brake. i adjusted the pedal play for the brakes thinking that maybe the arm for the master cylinder did not have enough range of motion and was not allowing the brake fluid to completely return to the master cylinder. this seemed to do the trick because this morning and all day today when i drove the car it was fine, but this afternoon on my way home i hit the usual traffic and about half way home the brakes started sticking again causing the motor to have to work harder to keep the car moving. not sure if its the back brakes or the front. when i got home and turned the car off there was a massive backfire and then coolant started pouring out of the car. all the coolant seems to be coming from the radiator which is new as of last week, but i cannot find anything wrong with is so far as i can see. waiting for the car to cool down to check it more thoroughly.

bop11

Sounds more like the thermostat is stuck or the fan belt has come off and you are over heating. Hot enough will tighten up the engine. Hot enough to self detonate the gas in the cylinder after turning ff the ignition. You may have warped the head but maybe not. Did the temp gauge top out? Stop and go driving puts a big heat load on the older cars.

Mhegel

The temp gauge was topped out when I turned it off. However it has a new radiator from the 289 HiPo and a 2300 cft electric fan that I have hooked up to a manual override toggle switch on the dash that I just leave on all the time except in the morning when it's warming up

barnett468

unfortunately, if your fan is chinese than it is not 2300 cfm.

if your rad is a std 2 row bit is too small . if it is chinese it is likely too small.

the cap may not fit properly.

it got hot because your brakes were dragging . . fix the brakes and it should not run hot unless you possibly blew a head gasket or something.

if your brakes were smoking, the shoes are likely toast.

racer_dave

^^^ agree with most of that. It overheated due to the extra strain on the engine. Never believe the cfm rating on fans. They are not accurate since they are measured in very controlled scenarios, none of which are actually on a car or attached to a radiator. I tend to use Derale on my racecars and have good luck with them.

The order of operations, at least to me is-

1- Get the drums turned. If it was hot enough to be burning the pads it was hot enough to warp the drums. Pads are burnt/glazed, get new ones.

2- Disassemble everything on the rear brakes and clean it all. Replace any wear items

3- Hone the wheel cylinders if you haven't.

4- Clean and lube the adjusters, make sure they are working.

5- Bleed the brakes. All the lines until you get clean clear fluid at the wheel. Start at the wheel furthest from the MC and work your way to the closest. Yes this is a pain in the *** and will take a long time but it needs to be done. Old brake fluid holds moisture. When the brakes warm up that moisture causes expansion, which puts more pressure on the pads which in turn creates more heat and on and on.

6- Reassemble everything make sure to get all the springs in the correct orientation. don't set the adjusters so the shoes are so close to the drums. Set them with a bit more room and then work into getting them closer to the drums.

7- Check the MC pedal throw/adjustment. You already checked this, just verify it now.

8- when you go on your test drive take the correct wrench to bleed your brakes. This way if a wheel does start to lock up you can release the pressure on that line and hopefully not ruin the pads/drum or overtax the engine

This may be a pain to track down but its solvable at home. good luck.