Testing vacuum (hard brake pedal)

[94250turbo]

Do i just buy one of those vacuum testers at autozone and hook it up to the brake booster? What should the readings be? Also do i just test it at idle?

 

[firehawk]

I used a large vacuum gauge and T'd it in to the brake booster. My vacuum was low, but a new vacuum pump fixed my problem with the brake pedal.

 

[fuzzy1626]

The vacuum gage installed in my truck stays on 22hg even at idle unless I step on the brake pedal.

 

[GOOSE]

You should be able to push down on the pedal with the truck off for a minute with minimal loss of vacuum. There is a list of tests in the factory service manual that are very helpful in diagnosing vacuum problems.

 

[FarmerFrank]

Not to hijack a thread too much, but is there a rebuild for a vacuum
Pump??

Is it just a diaphragm that goes bad inside?

 

[94250turbo]

I unplugged the booster hose from the manifold and put the vacuum gauge in its place. The gauge was between 20-25 hg . Was that an acceptable method to test my vacuum?

 

[94250turbo]

Could it be the brake booster? When I would apply the brakes there would be a "woosh" noise.

 

[madpogue]

If you have that good vacuum at the distro box, then yeah, the next prime suspect is the booster.

 

[vegas39]

Could it be the brake booster? When I would apply the brakes there would be a "woosh" noise.

Your booster is bad. I went through 4 or 5 autozone rebuilds before finally getting a good one. Every time I hit the pedal, it was kinda hard to push and they all sounded like I had air brakes.

 

[94250turbo]

I was about to buy the brake booster and decided to check the vacuum again and it is quite low. Where is the low vacuum switch located so I can do a few more tests.

 

[4x4manonbroke]

I installed T about 12" from pump where it goes to all the A/C stuff and then over to the Brake Booster, mine was 4hg ... talk about hard to stop ... lol

 

[79jasper]

I was about to buy the brake booster and decided to check the vacuum again and it is quite low. Where is the low vacuum switch located so I can do a few more tests.

Just follow the lines. It has a two wire plug.
Should be drivers side fender liner under the battery on obs trucks.
Same but passenger side on bricks.

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[94250turbo]

Can someone guide me on what puller i need to use for the vacuum pump pulley? Does harbor freight have one that will work? Anything i need to know about pulling it off and putting it back on?

 

[79jasper]

Power steering pump pulley puller.
Say that 5 times fast. Lol
Check it for oil before you put it on.
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[94250turbo]

Power steering pump pulley puller.
Say that 5 times fast. Lol
Check it for oil before you put it on.
Sent from my SM-G900R4 using Tapatalk

Check it for oil? Im supposed to lube the new pump?