hydraulic brake booster question

[chevak20]

I bought a truck, brake pedal that had long pedal travel, and I had to put much effort to get it to brake. The calipers are in good shape and are not stuck, which I had thought at first when I test drove it.

It is a diesel with hydro boost. Now the engine is out and it is about to be replaced but I need to buy brake parts now.

Question; do I have to replace the booster?/master? the master reservoir had very little brake fluid in the rear little hole. Booster doesn't leak but is a little wet around the piston inside the truck.

Should I repair it with a new valve repair kit or should I just flush the booster with new power steering fluid ( yes it is almost brown)? Or should I buy the remastered booster and master all together?

[Mkcustums]

Could be anything from a slipping belt, contamination of either power steering fluid or the brake fluid, a clogged line, binding / sticky pedal linkage. If it's low it should have got some air in it causing it to be soft. Worse case is a bad power steering pump or hydroboost unit. Power steering issues (slipping belt or bad pump) should be easy to spot cause it would be hard to steer. It wouldn't hurt to give all that a quick check out.

[chevak20]

This truck has been standing outside in a snowy cold climate and has not been driven for 8 years . The power steering was working fine. With the calipers, I am able to push the pistons in too, so the master is not stuck either.
I have not had time to check out the rear drums, though.
So contamination of the fluid can be a possible cause. It looked dark red to a brownish color ATF. Is it hard to change the valve with the repair kit Napa is selling?
Thanks

[Mkcustums]

Originally Posted by chevak20

This truck has been standing outside in a snowy cold climate and has not been driven for 8 years . The power steering was working fine. With the calipers, I am able to push the pistons in too, so the master is not stuck either.
I have not had time to check out the rear drums, though.
So contamination of the fluid can be a possible cause. It looked dark red to a brownish color ATF. Is it hard to change the valve with the repair kit Napa is selling?
Thanks

I've never rebuilt one before, so I honestly can't say. I have had rear drum brakes on a truck that that froze up that gave me a pretty solid pedal, wasn't hydroboost system but the same anyway.

I'm sure you know but the brake hydraulic system uses brake fluid only, while the power steering and hydroboost system use power steering fluid. Just don't mix the two up.

Looks pretty easy to rebuild if you did find it's the booster causing the issue.

[chevak20]

Thanks, it looks pretty simple to rebuilt one.