FZJ80 stiff brake when cold

[ranchero7]

I've had an odd problem come up on a few cold (10-15f) mornings. The first stop takes significant effort and seems like I won't be able to stop. In terms of braking power, it feels like air in the lines, but the pedal feels normal. I don't think it is ice on rotors as it has been really dry around here. After the first stop things are fine.
Will replace fluid and power bleed system soon. Any other thoughts?
Thanks
Steve

 

[Trapper50cal]

It happens...prob. has to do with the viscosity of the brake fluid that soon after very cold start up.

 

[Ebag333]

Calipers and brake pads don't function well when they're cold, and they won't stop as well until they warm up. If the calipers are sticky (need to be rebuilt or replaced), they can perform poorly when cold as well.

The first stop or two is usually not ideal, but you shouldn't have any difficulty in stopping. If you do, then there's something else wrong beside the usual "works better when warm."

Bleeding the system is very important on any vehicle, but especially 80's. An 80 that's been maintained will stop as well as any other vehicle in a similar class, and as well as many vehicles several thousand pounds lighter. An 80 with air in the lines will stop very poorly.

 

[BlueWithNV]

Brakes

Mine does that when i keep it outside when real cold out. My only guess would be that the 80 eats brakes. There might be some heat build up in the rotors/pads and then it gets parked. Over night, weather condtions are such that condensation happens and upon hitting the brakes on the way out of the driveway, they are frozen to the rotor. Just my theory.

 

[lostinafog]

replace vac brake booster.

it`s not as flexible as it should be in the cold old rubber ya know.

will giva a very firm pedal but no real assist to the master cylinder

 

[darwink1]

How about the brake booster check valve freezing? Is the 80 valve on the fire wall or at the booster?

D

 

[Ebag333]

It's part of the booster.

 

[ranchero7]

Thanks Fellas. I'll start with new fluid and a bleed with my Motive bleeder and figure out how to check the check valve.

 

[OffrdRN]

Hello everyone. I know this article is 10 years old but I'm having a similar issue. It's only now that it's cold and right on start-up. The brake is extremely hard and I don't have any "stop". After 15-30 seconds, it lossens up and the brakes work fine. Was wondering if anyone can give a novice like me a tip. Thank you in advance for your help and consideration.

 

[OffrdRN]

Hello everyone. I know this article is 10 years old but I'm having a similar issue. It's only now that it's cold and right on start-up. The brake is extremely hard and I don't have any "stop". After 15-30 seconds, it lossens up and the brakes work fine. Was wondering if anyone can give a novice like me a tip. Thank you in advance for your help and consideration.

Sorry, I have a 1996 LX450 if it helps, and the master was just replaced to get through inspection.