Manyal brake pushrod length question

[moparfanatic56]

I did a auto to 4sp conversion and a drum to disc brake converdion on my 72 dart and my front calipers do not want to release. My question is are the brake push rods the same length for this switch. The front calipers are new and I have tried 2 different master cyclinders with a 3rd one on the way to me. The brakes will release after about 5 to 10 minutes of sitting, any ideas on what I might be overlooking.
Thanks

 

[Professor Fate]

1.) Are you using a disc brake master cylinder (large rear reservoir, no residual valve in the port for front brakes)?
2.) Are you sure you have the lines plumbed correctly? (line to front brakes coming from rear reservoir, rear brakes to front reservoir- all via the proportioning valve, of course...)
And yes, the brake pushrod is the same length, disc or drum. But sometimes you still need to use an adjustable pushrod, just because parts have tolerances, and tolerances can stack up- and some new replacement parts don't meet spec to begin with.

 

[moparfanatic56]

1.) Are you using a disc brake master cylinder (large rear reservoir, no residual valve in the port for front brakes)?
2.) Are you sure you have the lines plumbed correctly? (line to front brakes coming from rear reservoir, rear brakes to front reservoir- all via the proportioning valve, of course...)
And yes, the brake pushrod is the same length, disc or drum. But sometimes you still need to use an adjustable pushrod, just because parts have tolerances, and tolerances can stack up- and some new replacement parts don't meet spec to begin with.

1)Yes.disc/drum master cyclinder. Large reservoir in the rear.
2) all plumbed correctly, all new inline tube brake lines front to rear.i have also put 2 new distribution blocks in, the first one had a bad seal in it.

 

[Oldmanmopar]

yup

 

[Inertia]

Loosen off the 4 Master cylinder mounting bolts a coupla turns each, to create some clearance to the mounting surface, see if that cures the issue.
If it does, you need a shorter pushrod, maybe grind a few thou off the end of the rod. or adjustable ones are avail.

If the front calipers have black plastic pistons, return them for ones with metal pistons, jmo

 

[44o gts dart]

I did a auto to 4sp conversion and a drum to disc brake converdion on my 72 dart and my front calipers do not want to release. My question is are the brake push rods the same length for this switch. The front calipers are new and I have tried 2 different master cyclinders with a 3rd one on the way to me. The brakes will release after about 5 to 10 minutes of sitting, any ideas on what I might be overlooking.
Thanks

Just saying I have seen the brake light switch out of adjustment and holding pedal in,, might be easy to check