C10 Brake Booster

[Mike-P]

Hey guys,

I installed a brake booster on my truck earlier today. I was told it worked by the person I got it from who repainted it and gave it to me when they sold the truck. I attached the vacuum line on the front of the manifold. Put everything on and the braking doesn't seem to be much easier than when I just had the master.

Do you think that this could be a faulty booster or perhaps the brake needs to be adjusted? I almost have it fully extended with leaving about 6-7 threads on the adapter.

A bit stumped here. (Did the typical youtube tests and it doesn't seem to be getting any stiffer when stepping on the pedal after vehicle operation).

Any help would be much appreciated.

Thanks,

Mike

[everettelane]

To be clear did you remove the master cylinder and now the pedal goes to the floor and does not pump up, or did you just add the vacuum booster and the pedal is still hard to push like with manual brakes? I would check the vacuum pressure and maybe use a hand held vac pump like mighty vac it should take between 18 to 22 in of vacuum to operate the diaphragm.

[Mike-P]

I removed the master cylinder from the wall, installed the booster on the wall and installed the master cylinder onto the booster. It is still hard to push like manual brakes. I was told I didn't have to bleed the brakes as this was already done by the former owner recently...

I'll have to measure the vacuum pressure. Thanks for your message.

-Mike

[everettelane]

Originally Posted by Mike-P

I removed the master cylinder from the wall, installed the booster on the wall and installed the master cylinder onto the booster. It is still hard to push like manual brakes. I was told I didn't have to bleed the brakes as this was already done by the former owner recently...

I'll have to measure the vacuum pressure. Thanks for your message.

-Mike

if the booster can't hold vacuum it probably has a hole in it or dryrot and will not improve the pedal feel.

[Andy4639]

Booster test.
With motor off put foot on brake then start the truck does the brake pedal go further down? If so the booster is working as it should. If not check the booster.
Did you check to see if the rod inside the booster is coming into contact with the master cylinder plunger. Some times you have to add a spacer.

[Mike-P]

Originally Posted by Andy4639

Booster test.
With motor off put foot on brake then start the truck does the brake pedal go further down? If so the booster is working as it should. If not check the booster.
Did you check to see if the rod inside the booster is coming into contact with the master cylinder plunger. Some times you have to add a spacer.

Hi Andy,

Was going to do that exact check today. If it isn't contacting, can you buy the spacer from your local autoparts store?
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[Mike-P]

So I took off the Master Cylinder to check this today and appears that it is coming out enough. In fact, the pedal was able to move further(1.5-2") after removing the Master. I also made sure the check valve was still working.

The booster worked smoothly and effortlessly once the master cylinder was off. But, I do understand there was nearly no resistance with the master cylinder disconnected.

At this point, I think it may be low vacuum pressure(Which is my next test), faulty booster, or perhaps I somehow kinked or altered the master cylinder lines when installing the booster.

-Mike

[Mike-P]

She's pulling between 16-17 inches of vacuum at idle. So, it leads be to believe the brake booster must be at the end of its life since the manual brakes were working fine before installing the booster.

[Andy4639]

Originally Posted by Mike-P

Hi Andy,

Was going to do that exact check today. If it isn't contacting, can you buy the spacer from your local autoparts store?
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That I'm not sure of. I have herd of people making them though.

[Mike-P]

Picked up a new booster this afternoon and turns out the used one I had was faulty. 👌 Brakes work great
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[everettelane]

Originally Posted by Mike-P

Picked up a new booster this afternoon and turns out the used one I had was faulty. 👌 Brakes work great
Posted via Mobile Device

Persistence is the key, Glad you got it!!