Troubleshoot back brakes?

[Saul]

Hi guys.

I'm having a problem with my back brakes. I bleed them and they grab/work fine - but if I let them sit overnight the next day they dont work.

Is it a sign of still having air in the lines or is there a leak in the system somewhere?

1982 R btw.

[Erics350x]

sounds like a leak, look around the caliper piton and the push rod on the master for fluid

[Saul]

sounds like a leak, look around the caliper piton and the push rod on the master for fluid

So would you figure, if they work fine for an hour after bleeding it's more then likely a leak somewhere and not air still trapped in the lines?

[oscarmayer]

the master cyclinder could have a worn piston(seal?) that allows a slight a air leak. it may not leak fluid but coudl allow airt to seap into the vaccumed system.

[KASEY]

i usually put a 3 foot long piece of gas line on the caliper and pump the pedal till the fluid goes around a couple of times to get all the air out,,, just put the end back in the resiviour and you would be suprised how long it takes to get ALL the air out...

[Saul]

i usually put a 3 foot long piece of gas line on the caliper and pump the pedal till the fluid goes around a couple of times to get all the air out,,, just put the end back in the resiviour and you would be suprised how long it takes to get ALL the air out...

so, even if I get the brakes working and working good (they were solid!) I should probably still keep bleeding them quite a number of times after that initial 'working' period.

Once I got them working I only kept bleeding the lines another 5 or 6 times and figured it was good.

[cr480r]

If you have to re-bleed them to make them work again then something isnt right... air is entering the system while its parked...

[3wheelerlouie]

i had the same issue on my 83 and turns out that i removed a bolt that adjusts the brake pedal and was leaking the pressure back into the master , not sure why but after i re-adjusted that dang bolt it quit leaking...