Brake Master Cylinder Rebuild Kit - Help needed (1 Viewer)

[CombatWombat]

Hi all,

I own a '88 HJ61. I bought a NOS Brake Master Cylinder Rebuild Kit (04493-60160 – Part number should fit acc. catalouge) but the "adapters" (47218/47219 on the drawing) in the kit look different than the ones that are installed.
Does anybody know if they can be used? Are these some kind of residual pressure valves for drum brakes?

Thanks!
Sebastian

 

[OSS]

I know you’re not going to want to hear this but….
Even if you got the right kit with all the correct parts, a DIY brake master cylinder rebuild is usually doomed.
The problem lies in the cylinder bore itself. The usual reason the seals wear out is because the cast iron bore has rusted and rust pits have developed in the once smooth bore which acts as a file on the rubber - grinding it down.

If the bore never rusted inside, the seals likely would never need to be replaced (nor cylinder rebuilt) because they wouldn’t wear out.

Basically what I’m saying is: If the master cylinder is leaking or not working properly — it’s best to replace it.

 

[CombatWombat]

Yep, you're right. Checked the bore and it has rusted... I will get a new one.

Still I don't know if I should use this type of valve for my rear drums.

 

[OSS]

Each component of the original brake system is balanced with regards to the entire system. The original brake booster’s performance matches the master cylinder’s performance which matches the brake cylinder’s and caliper’s performance. Each component is part of a whole.
When things can get wonky is went swapping in newer higher performance parts piece meal. Like just upgrading the booster. or just upgrading the front calipers.

Doing something like that unbalances the system snd braking may change tothe worse- one axle brakes to strong or another locks up or the pedal feel is twitchy.

Unless you’re going to replace everything with all upgraded parts from another vehicle, my vote is to keep everything original.