Brake vacuum booster testing using a vac pump (1 Viewer)

[alia176]

This is a dumb question but I got a strange behavior to report out of my vac booster. I disconnected the hose from the intake manifold and stuck a Blue point suction pump deal on it. It holds vacuum no problem. I operate the brake peddle and the vac slowly goes away with each pump.

Here's where things get weird. I try to create a vac again but no vac is created. I have a leak of some sort, I think but not sure.

On the road, the 80 stops fine, no weirdness. I'm just chasing down all of my vac leaks which become turbo boost leaks while on boost and came to this area of the engine bay. I'm also chasing down P0171 "too lean" condition which can be triggered by pirate air not accounted for by the MAF.

The check valve and the hose at the booster are brand new and came with the turbo install kit.

Ideas?

 

[BILT4ME]

This is a dumb question but I got a strange behavior to report out of my vac booster. I disconnected the hose from the intake manifold and stuck a Blue point suction pump deal on it. It holds vacuum no problem. I operate the brake peddle and the vac slowly goes away with each pump.

Here's where things get weird. I try to create a vac again but no vac is created. I have a leak of some sort, I think but not sure.

On the road, the 80 stops fine, no weirdness. I'm just chasing down all of my vac leaks which become turbo boost leaks while on boost and came to this area of the engine bay. I'm also chasing down P0171 "too lean" condition which can be triggered by pirate air not accounted for by the MAF.

The check valve and the hose at the booster are brand new and came with the turbo install kit.

Ideas?

My booster worked fine for years until I left for work for 2 weeks and when I got back and drove it, the brake pedal was hard as a brick.

After I changed the booster most of my engine stumbling went away. I did not realize how much air I had been losing, even though the brakes had been working fine.

I regularly reset my computer (pull the EFI fuse) to improve mileage due to changing driving conditions, so it's not like the stumble wasn't there before or that it suddenly showed up. I'm very much on top of my maintenance and it surprised me how much of a change there was in how the engine ran, when I was not expecting any change whatsoever.

 

[alia176]

This is great info, thank you for that! So, you didn't experience any issues until the very end, interesting. My pedal is totally normal and the braking performance is great.

This particular behavior is strange to me. My unit maybe just fine but I need to be sure, hence this post. Everything on this rig is long in the tooth

Where did you get your booster from and what was the cost? I'm thinking no refurbished unit, just go for new?

Rockauto

NAPA

Partznet

Cruiseryard

 

[Shipwreck]

Where did you get your booster from and what was the cost? I'm thinking no refurbished unit, just go for new?

Here for OEM:
80 Series, NEW OEM Seiken Brake Booster and OEM Gaskets (2), 44610-60792 - http://www.cruiseryard.com/80-series-new-oem-seiken-brake-booster-and-oem-gasket/

Follow through with your vacuum diagnostics first though. Brake pedal pressure typically gets rock hard when the booster fails.

 

[alia176]

Here for OEM:
80 Series, NEW OEM Seiken Brake Booster and OEM Gaskets (2), 44610-60792 - http://www.cruiseryard.com/80-series-new-oem-seiken-brake-booster-and-oem-gasket/

Follow through with your vacuum diagnostics first though. Brake pedal pressure typically gets rock hard when the booster fails.

Copy, updated my thread and will do.

 

[BILT4ME]

This is great info, thank you for that! So, you didn't experience any issues until the very end, interesting. My pedal is totally normal and the braking performance is great.

This particular behavior is strange to me. My unit maybe just fine but I need to be sure, hence this post. Everything on this rig is long in the tooth

Where did you get your booster from and what was the cost? I'm thinking no refurbished unit, just go for new?

Rockauto
View attachment 2692277

NAPA
View attachment 2692278

Partznet
View attachment 2692279

Cruiseryard
View attachment 2692313

I bought mine new Toyota from Partsouq.
4461060792 $420.98
4478535020 $0.74 Booster Gasket
4477360150 $28.16 Hose, union to check valve
Shipping was $67.46 for a total of $517.34
I forgot to order the gasket between the MC and the booster. Make sure you order that one as well.

I need to adjust my booster plunger to get my brake pressure back. I forgot to do that when installing. I have to push really hard for my brakes.

 

[alia176]

Thank you sir!!