Brakes seem to start getting hard/stiff by after a long drive. Still hard for a few hours after but by the next day they are normal again.

[tonyp25]

72 RR 440. Brakes are fine for about the first 30 minutes. Stops well too. Drums all the way around. Then they start getting a little hard. Once I park it the brakes seem to be even harder but by the next day they are normal again. Any ideas?

On short drives they don’t seem to get stiff at all or harden up after parking. Any idea what could cause this?

 

[pnora]

Manual or power brakes? If power it sounds like the booster is losing assist.

 

[j-c-c-62]

Not clear, is the pedal firmer, or is it you need to press harder to get the same braking effect you had up to the first 30 minutes of driving?

 

[Geoff 2]

It could be the type of brake shoe [ lining ]. As the material warms up, it loses it's braking efficiency. Try a different brand of brake shoe.

 

[BeatersRus]

kinda sounds like the brake hoses are due for replacement.
change both sides.

 

[tonyp25]

Not clear, is the pedal firmer, or is it you need to press harder to get the same braking effect you had up to the first 30 minutes of driving?

Good question. I almost need to drive it again just so I can be sure. I would say firmer. It feels like I have to use a lot more force to press it down and the pedal only moves a little bit. But still stops fine.

When normal it feels like a regular cars brakes if that makes sense.

 

[Don Frelier]

Good question. I almost need to drive it again just so I can be sure. I would say firmer. It feels like I have to use a lot more force to press it down and the pedal only moves a little bit. But still stops fine.

When normal it feels like a regular cars brakes if that makes sense.

Sounds like a booster problem.

 

[tonyp25]

Sounds like a booster problem.

I might be dumb on this but I don’t see any booster. The car is new to me (within 6 months) I believe it is manual brakes. At least that’s how I always told the difference (booster = power and no booster = manual). Unless that isn’t always the case.

I had a 67 that had a booster and maybe what’s called a vacuum assist thingy too and those brakes ruled.

 

[SlingLow]

I just fixed this problem on a 65 Merc with a new master cylinder. It wasn't allowing the fluid to return to the reservoir. Another possibility is weak rubber brake lines that collapse on themselves which requires replacement of the lines as @BeatersRus said.

 

[j-c-c-62]

I just fixed this problem on a 65 Merc with a new master cylinder. It wasn't allowing the fluid to return to the reservoir. Another possibility is weak rubber brake lines that collapse on themselves which requires replacement of the lines as @BeatersRus said.

Does normal possible road heat cause that pressure buildup that is restricted?

 

[Fran Blacker]

A residual valve(s) in master cylinder? Holds back brake fluid from returning to master. Letting car sit lets fluid to return or you have a rubber hose problem.