I am stumped with the brakes on Tux

I have the car up on stands rear wheels off, waiting for some cool down, then check all out in the drums.
 
Boydsdodge said:
Uncross your fingers.
Went for test drive, things are getting worse. Rear brakes are staying loaded, smoking on return to garage after 20 min drive. wheels off ground I can barely turn. loosened master to see if I was as stupid as I am starting to feel. no difference. Loosened rear brake line at master to see if it was holding pressure. no change. tried parking brake, locks tight, released parking brake, very tight wheels.
Still hard pedal.
I took temps when I returned, right rear 205 deg, left rear 195 deg. Fronts 150, all temps taken between lug nuts on wheel.
I didn't think the crack in hose was going to be the cause.
Click to expand...
Crack a rear bleeder and see if it releases.
 
Brand new rear hose. Brand new everything except the combination valve. I can order a new hose but won't see till Monday.
Hard to think it.
Can the combination/metering valve cause these problems?
 
Iwould try backing off the rear brake adjustment about 1 turn and see what happens. Also did you accidentally swap the front/rear lines at the master cylinder? Just a guess.
 
John Kirby said:
Iwould try backing off the rear brake adjustment about 1 turn and see what happens. Also did you accidentally swap the front/rear lines at the master cylinder? Just a guess.
Click to expand...
Thanks for reply. No, the lines are in correct location
 
Boydsdodge said:
Hello, I think I need some input or knowledge help with the brake problem on my Imperial.
1973 Imperial, New Raybestos pads and shoes, rebuilt and restored booster, new master cylinder, then back to the original master, new rear wheel cylinders, new flex lines front rear, all new brake hardware in drums, new NOS calipers.
I have had a hard pedal with slow stop since I brought Tux home. I pulled the booster and had it rebuilt, it failed booster test with vacuum and had plenty of old brake fluid crystallized inside. Also had booster replated.
Installed booster but bad winter, held off on road test till April. Once road tested I still had a hard pedal, so I thought it might be a faulty new offshore master cylinder I had installed with booster. replaced with good working Chrysler master from Imperial.
Still hard slow stopping.
Replaced front calipers that I rebuilt earlier with NOS calipers, I was thinking maybe my old calipers were hanging up.
Still hard pedal and slow stop.
I replaced the pads and shoes with new wheel cylinders and all drum hardware.
Same feel, this time I feel the pads grabbing better, car stops straight as it always has, but it is still a hard pedal slow stop. While sitting at a light waiting for change, the pedal almost feels as if its starting to push back.
I took Imperial out for a 40 min drive on two lane, urban main and side streets.
As I was on the return run I could feel pulsing brake grab on side streets. Not enough to stop the car, but enough to create a pulse slowing pulse in the car. This is new, but may be because new pads and shoes grab better the the asbestos.
Could this be the combination/proportioning valve?
Could the metering valve be stuck?
I have not had this problem before, all the cars I have done over the years, I have had symptoms like this but it was booster, seized calipers, etc...
Running out of time for the big Carlisle drive.
Extra input. Brakes get harder after first few stops, hard from start. I have been bleeding brakes with hose into jug of brake fluid with steading push of pedal until no air and pedal hard.
Thinking I might try another master.
Thanks.
Click to expand...
I'm looking at doing the brakes on the '73 as well, which supplier did you get the parts from?, did you have to quote specific part numbers or just year/make of vehicle? Thanks.
 
crv said:
I'm looking at doing the brakes on the '73 as well, which supplier did you get the parts from?, did you have to quote specific part numbers or just year/make of vehicle? Thanks.
Click to expand...
What part numbers are you after? I will gladly make a list.
 
This needs to be put in place close to the booster
www.dormanproducts.com

Dorman Products - 80195

Power Brake Filter
www.dormanproducts.com www.dormanproducts.com

Filter check valve assy, works great! Now with a vacuum source start checking the operation of the pedal from the manifold connection end of the hose. More than several times.

The emergency brake cable adjustment needs be backed off as it probably is advancing the rear shoes position away from the "home" position. I have seen this too many times now.

As far as pad and shoe material-please stop the old thinking that asbestos materials are superior to today's modern materials-that is complete hogwash. Carbon metallic is the best choice. Drum brake cars stop like disc brake cars with the proper materials! Prove me wrong- you can't and no one will try it because they will find out i am correct. lol You can't make this $%@# up

The rear shoes need to be placed in the drum, pushed against the drum and a feeler gauge used to see how much difference there is between the arc of the shoe and the arc of the drum. If this is not done the shoe will never fully cantact the drum! That's a geometry thing. I forgot what the rule of thumb was for the gap distance. Call a real Clutch & brake company who has the tools to measure and arc the shoes to match the drum and ask what the spec is. I took Automotive Braking Systems class 101 and 201 in technical college college and i paid attention. HA!
 
Ripinator said:
Does this mean you finally found the problem?
Click to expand...
I think I might have found the cause. I have not repaired it yet, but I think it might be the cast iron combination valve. I purchased a rebuild kit for the valve, I plan to do it now that the show season is winding down and when I get TB up to sale condition.
I will post the repair and rebuild photos.
 
USSMOPAR said:
As far as pad and shoe material-please stop the old thinking that asbestos materials are superior to today's modern materials-that is complete hogwash. Carbon metallic is the best choice. Drum brake cars stop like disc brake cars with the proper materials! Prove me wrong- you can't and no one will try it because they will find out i am correct. lol You can't make this $%@# up

The rear shoes need to be placed in the drum, pushed against the drum and a feeler gauge used to see how much difference there is between the arc of the shoe and the arc of the drum. If this is not done the shoe will never fully cantact the drum! That's a geometry thing. I forgot what the rule of thumb was for the gap distance. Call a real Clutch & brake company who has the tools to measure and arc the shoes to match the drum and ask what the spec is. I took Automotive Braking Systems class 101 and 201 in technical college college and i paid attention. HA!
Click to expand...

I'm finding your assertion re metallo-carbon shoes to be sound, as that's what I use on the rear. Mind you CHEAP CRAP shoes really can be bad, but I've used good metallo-carbon shoes on the rear brakes of my Newports for over 5 years nbow, with good results. I DO like the old asbestos shoes up front, but only because I've been able to score them pretty cheap, and now have a long term supply.

Scored a good old shoe caliper this past summer too. Makes things easy for checking if shoes are in round w the drums. Thanks for your post.
 
Boydsdodge said:
Hello, I think I need some input or knowledge help with the brake problem on my Imperial.
1973 Imperial, New Raybestos pads and shoes, rebuilt and restored booster, new master cylinder, then back to the original master, new rear wheel cylinders, new flex lines front rear, all new brake hardware in drums, new NOS calipers.
I have had a hard pedal with slow stop since I brought Tux home. I pulled the booster and had it rebuilt, it failed booster test with vacuum and had plenty of old brake fluid crystallized inside. Also had booster replated.
Installed booster but bad winter, held off on road test till April. Once road tested I still had a hard pedal, so I thought it might be a faulty new offshore master cylinder I had installed with booster. replaced with good working Chrysler master from Imperial.
Still hard slow stopping.
Replaced front calipers that I rebuilt earlier with NOS calipers, I was thinking maybe my old calipers were hanging up.
Still hard pedal and slow stop.
I replaced the pads and shoes with new wheel cylinders and all drum hardware.
Same feel, this time I feel the pads grabbing better, car stops straight as it always has, but it is still a hard pedal slow stop. While sitting at a light waiting for change, the pedal almost feels as if its starting to push back.
I took Imperial out for a 40 min drive on two lane, urban main and side streets.
As I was on the return run I could feel pulsing brake grab on side streets. Not enough to stop the car, but enough to create a pulse slowing pulse in the car. This is new, but may be because new pads and shoes grab better the the asbestos.
Could this be the combination/proportioning valve?
Could the metering valve be stuck?
I have not had this problem before, all the cars I have done over the years, I have had symptoms like this but it was booster, seized calipers, etc...
Running out of time for the big Carlisle drive.
Extra input. Brakes get harder after first few stops, hard from start. I have been bleeding brakes with hose into jug of brake fluid with steading push of pedal until no air and pedal hard.
Thinking I might try another master.
Thanks.
Click to expand...
This is called kick back …..the booster is not working …THE POPPIT VALVE ( control valve in rear hub) has failed.
Dozens of videos on this ,and booster testing…TRM
This is textbook, any rebuilder for a living knows this…
Textbook case…..TRM
Uncle Ron and self…….over 10,000 MOPAR boosters since 71
 
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