Dragging calipers on my '73 conversion

[Zymurgy]

I have put around 120 miles on my '66 300 since my conversion everything new including the hose lines. After the first 50 or so the left side hung up and got really hot. I pulled over waited 5 minutes drove home no other problems with the left side since. I then was out for a cruise and and this time about 30 miles in the same thing happened but to the right side. I was near home so just parked it.

I had left the clips off shown in the picture, so today I installed them. I drove about 30 miles in 10 miles chunks today, at the end on the 20 miles the right side again started dragging a bit. I jacked it up and the right wheel was hard to turn, let it cool drove another 10 miles and the right side overheated again.

One addition tidbit, I had my distribution block all screwed up initially. Only the right side was working and I was hitting my brakes pretty hard during a couple of test drives, could I have damaged the right hose?

I have Raybestos calipers I ordered on-line. Everything else I ordered from Auto Zone including Duralast pads and hoses. I can pick up a Duralast caliper for $30 from AutoZone, or should I pick up a new hose first and replace it.

It stops perfectly and very responsive, no air in the lines, excellent pedal feel, otherwise.

 

[cantflip]

I have put around 120 miles on my '66 300 since my conversion everything new including the hose lines. After the first 50 or so the left side hung up and got really hot. I pulled over waited 5 minutes drove home no other problems with the left side since. I then was out for a cruise and and this time about 30 miles in the same thing happened but to the right side. I was near home so just parked it.

I had left the clips off shown in the picture, so today I installed them. I drove about 30 miles in 10 miles chunks today, at the end on the 20 miles the right side again started dragging a bit. I jacked it up and the right wheel was hard to turn, let it cool drove another 10 miles and the right side overheated again.

One addition tidbit, I had my distribution block all screwed up initially. Only the right side was working and I was hitting my brakes pretty hard during a couple of test drives, could I have damaged the right hose?

I have Raybestos calipers I ordered on-line. Everything else I ordered from Auto Zone including Duralast pads and hoses. I can pick up a Duralast caliper for $30 from AutoZone, or should I pick up a new hose first and replace it.View attachment 122125

It stops perfectly and very responsive, no air in the lines, excellent pedal feel, otherwise.

You're holding pressure... A drum brake master may have a residual pressure valve built in, or in the combination valve(proportioning valve) that would hold a small pressure on the system.The booster has an adjustment on the push rod for the master cylinder... or perhaps you have overfilled the reservoir, taking up all available expansion space. Leave 1/4 inch or so to the top of the reservoir when filling.

The book test to make sure the master cylinder compensating ports are open involves a helper pushing the pedal while you look for turbulence at the ports... this is a great way to get fluid all over your paint. A piece of plexiglass may help, but you should do the test with the engine running, so the booster is under vacuum. A stock system would have a hold off valve, so you will need the assistant to start with light applications and increase effort on multiple pumps until the front circuit starts to work.

 

[commando1]

Jeff, you are on my speed dial for my next brake problem.

 

[live4theking]

Jeff, you are on my speed dial for my next brake problem.

Jeff has already been tremendously helpful to me.

 

[Ross Wooldridge]

Yup - one thing is to check your flex hoses - they can look good on the outside and collapse internally, and don't release pressure.

 

[cantflip]

Jeff, you are on my speed dial for my next brake problem.

AHH... The words every driveability guy loves to hear...

At least you're close enough if I need to come look for myself, Mike would have to wait for July for me to get there.

And you know I love the problem solving side of things, which may help to explain some of the dents in my head...

 

[traintech55]

Pretty sure you changed the flex hoses with the caliper. I am with Jeff on this one, if you did not put on a disk brake master cylinder, the residual port will restrict the fluid. Send me a PM, and I will go thru step by step on how I did my 300.

 

[Zymurgy]

Thanks big time. I have somethings to check. I do have a new correct disc master. It could be overfilled would have never thought of that.

 

[70bigblockdodge]

You have the rear to the front, and the front to the rear, not trying to be a smart *** just mentioning.

 

[Zymurgy]

You have the rear to the front, and the front to the rear, not trying to be a smart *** just mentioning.

Legit question. I had the distribution block backwards and I initially had it all screwed up. The divided rear section was going to the right front, the other section was going to both the rear and left front. It didn't work too well in that set up.

 

[cantflip]

Legit question. I had the distribution block backwards and I initially had it all screwed up. The divided rear section was going to the right front, the other section was going to both the rear and left front. It didn't work too well in that set up.

Try this http://www.mymopar.com/downloads/servicemanuals/1973_Dodge_Chassis_Service_Manual.zip
Check your brake pedal freeplay, under stop light switch adjustment... don't try to change it, just a possibility that too little free pedal movement (key off) would be present if the booster adjustment is too tight (long). Not a conclusive test. Bottom right corner of 5-15 describes the recommended test for the compensation ports (booster push rod adjustment) titled "Testing Master Cylinder" and this is the one that will hurt your pretty paint if not done with extreme care.

The residual pressure valve is covered in the master cylinder section, and the proportioning valve section should help you feel better about your connections.

If you feel insecure about your lines being in the correct locations, I have a 76 manual with nice diagrams that you could interpret well enough into your system layout. I may need to wait for Management to return from work to make the scans though.

p.s. If you get brake fluid on paint, flush immediately with lots of water. Every second you wait is a greater chance of color change or the paint wrinkling and falling off. Water soluble, no cleaners or solvents.

 

[Zymurgy]

Thanks again, I know I have the lines correct now, in distribution block, I did it wrong four years ago, the disc brake conversion amplified it tenfold and made it undriveable.

 

[traintech55]

When I did my 300 I kept both front and rear seperate and installed an adjustable prop. valve in the rear line. Works fine.

 

[mr. fix it]

so all is good now Mike?

 

[Zymurgy]

so all is good now Mike?

No trying to figure it out still, but have great information to look into this weekend.

 

[Zymurgy]

When I did my 300 I kept both front and rear seperate and installed an adjustable prop. valve in the rear line. Works fine.

That is how I have it set up too. Just trying to find my gremlins

 

[Ripinator]

That is how I have it set up too. Just trying to find my gremlins

 

[mr. fix it]

I've seen calipers cease up too Mike..

 

[mopar_4life]

I've seen calipers cease up too Mike..

Working 11 years at the AZ(Where Duralast is from...) I have seen calipers come back because of various issues. It should have a lifetime warranty so it might be worth just taking it back in just to eliminate that as a possibility.

 

[Zymurgy]

Try this http://www.mymopar.com/downloads/servicemanuals/1973_Dodge_Chassis_Service_Manual.zip
Check your brake pedal freeplay, under stop light switch adjustment... don't try to change it, just a possibility that too little free pedal movement (key off) would be present if the booster adjustment is too tight (long). Not a conclusive test. Bottom right corner of 5-15 describes the recommended test for the compensation ports (booster push rod adjustment) titled "Testing Master Cylinder" and this is the one that will hurt your pretty paint if not done with extreme care.

I downloaded the manual, very nice to have the additional information. First the reservoirs were not over filled about 3/8" of air space, next I did the "Testing Master Cylinder" it seems to fail this test. No movement of fluid noticed definitely not a geyser of fluid squirting up into the reservoir. What exactly does this tell me? Bad master?

There also seems to be very little pedal movement. My dual brake booster was sent to a highly recommend place to be rebuilt.

I then proceeded to take it out for a spin drove about 30 miles back roads, starting and stopping. Normal stopping, hard stopping and never got the the calipers to hang up. Personally the brakes felt perfect but there does seems to be very little pedal movement.

Additional trouble shooting out of '73 manual for reference.