1980 720 kingcab front brake locking

[longcreek]

I have a 1980 720 kingcab and the right front brake caliper does not release. New calipers both sides as well as new flex. lines but no help. Does the brake proportion valve cause the right front to not release or?? truck pulls very strong to the right when braking.
Thanks

[themadscientist]

Prop valve only splits front to back bias. Your hard line may be kinked. You press the pedal and there is enough force to get fluid to the caliper, but not enough to let fluid easily flow back the other way. That, or you have a sticking piston in the offending caliper. Just because it's new doesn't mean it works necessarily.

[sx moneypit]

Check this forum out > datsun-720-forum.html

Welcome to NICO!

[Dattebayo]

I would suggest replacing the hoses from the metal lines out to the caliper. If they're rotten inside from moisture, etc, they would lock a little bit. It happened to me once.

I would also say check the ABS block if you had it, but you don't. Most definitely not.

[longcreek]

Thanks for the comments, I have replaced the hoses and checked for bent lines etc. guess it must be the new caliper??

[themadscientist]

Might be. It may just need to have the piston pushed back in and cycled a few times. Just leave the hydraulics connected and pull it off the rotor. Compress it with the proper tool. I'll look the other way if it's a C-clamp. Be sure to be ready for fluid overflow at the master cylinder. Slide it back over the rotor and press the pedal again and repeat at least one more time. Bolt it back up, take it for a spin and see if you fixed it.

[300ZXttZMAN]

OP Welcome to nico!