Testing A Power Brake Booster

[kentdaryl]

Anyone know a good way to bench test a power brake booster? I have one a member is interested in, but the truck I got it off was never driven by me, so I'm not sure of the condition and don't want to sell him junk.

[Hawkrod]

No, no way to actually bench test that will tell you much. You can put a master cylinder on it and use a vacuum pump to make sure the diaghram is not perfortated but that is all you can do. Hawkrod

[kentdaryl]

Yeah Hawkrod, I couldn't think of a way either. I'll price it out like it's a core. Thanks

[fordman]

what i have done in the past is to putthe hose back on them and suck on the hose and see if i can get a sucksion (SP) to hold. if i can it must be good. if not i wouldn't call it a good one. just a core.

[Hawkrod]

As I already noted above, just because it holds vacuum does not mean it works. If you call them good because they past your "test" you are eventually going to cause somebody a lot of trouble. I have several dual dighram cores here, they hold vacuum just fine but they don't work for dog doo. Hawkrod

[fordman]

this test is a way to test it without using a vacuum pump. it just depends on how long you can hold your breath. its a fast way to tell in a junkyard if you have a chance. i always like to test mine on running trucks. if and when i can. if the engine runs rough with it hooked up then it could be bad. if the engine runs good with it on it is probably ok. just push on the brake to test it all the way. if you just hook it up without the brake pedal hooked up. its 50/50 chance that its good if the engine runs ok with it hooked up. i just pulled one from a good running truck. it didnt have any brakes on it. so i pulled it . when i did the booster was full of brake fluid. so it is probably bad with the brake fluid in it.

[bjde0b]

I just bought this one at a salvage yard yesterday. When I suck on it, it holds pretty good. I forgot to pull the block that the vacuum lines attach to on the intake manifold. Could anybody give me some information about this thing? I remeber there was a couple other vacuum lines on the same attachment.

Thanks.

[fordman]

what year booster is it? 67 boosters and trucks use a 1 year only booster. 68-77 1/2 use the same fitting booster. the 67 booster has a shorter rod i think than the 68-77 1/2 boosters do. thats the only difference i know of. here are some pics of some vacuum tees i have here. this brass one came off of a 390. i have one for a 302 but i cant find the pic right now. it has five total opening to hook tubes to it. the main one for power brakes and then four smaller ones for whatever else.

[bjde0b]

That is exactly what it looked like. I might have to run back out there and pull it off before I head back to Texas.