Brake light

[BrianX128]

So tonight on my way to work my brake light on my 6.9 came on. Its done this at random since i bought it. But then randomly my brakes got so hard i could barely stop the truck.

Im assuming I need a new vaccuum pump? Brakes have been perfect up until this and the reservoir is full..

 

[Thewespaul]

Check vacuum at the pump and if it’s good work your way back, if you have no leaks on the lines then booster may have failed.

 

[BrianX128]

If i dont have a gauge to test it can i just take the line off at the T and test it somehow? See how hard it pulls against my arm or something?

 

[Thewespaul]

Get a vacuum gauge, it’s a very useful tool for working on old vehicles. Otherwise you can pull the line off and see if it sucks at all.

 

[BrianX128]

Ok. For all i know there is probably 7 of them in a drawer my grandpa had in the garage. I'll have to check. Brake booster was new it was replaced a month before i bought the truck not to say it isnt bad but i bet this stupid vacuum pump will be the culprit.. the hose going into the booster felt loose too though so who knows. I hate when stuff like this happens right before work so i can sit and panic over it..

 

[Thewespaul]

There’s a check valve that hooks up to the booster there, they can crack and leak there maybe why it’s loose there.

 

[BrianX128]

Ok ill have to check that out too. Its the plastic piece going into the booster that moved not the hose to it if that makes sense

 

[chillman88]

Ok ill have to check that out too. Its the plastic piece going into the booster that moved not the hose to it if that makes sense

That plastic elbow thing is the check valve. Check the grommet too just in case.

 

[BrianX128]

I was just thinking when i was working on my ignition wiring i was under feeding wires around the brake area.. wonder if I disturbed a vacuum line to the brake petal area? Its a non cruise though so i don't think it has one..

 

[IDIBRONCO]

You should be able to move the check valve in the grommet, just not freely. It should take a little effort.

 

[genscripter]

You are so lucky your vacuum pressure sensor still works. When my vac pump fails, I only find out when my brake assist doesn't work.

 

[BrianX128]

So when i drive this stupid thing home from work at 3am basically i have brakes but i gotta press pretty damn hard for them to kinda function right?

 

[BrianX128]

So, I just ran outside and started the truck and pulled the vacuum line from the booster and stuck my thumb on it. I felt it pulsing and it would let me hold it up in the air by vacuum, but it didn't take more then wiggling it around in the air to get it to fall off of my thumb.. I'm guessing it's supposed to be a lot stronger of a vacuum than this? I know it would be more helpful to test it right, but I'm at work until 3am and I now work at a hospital so I don't have.. anything useful here lol.

 

[BrianX128]

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She's dead. Most i got at idle was 8, 14 ish at wot while it was in the truck but if you pressed the brake down it would go to 0 and took forever at idle to even get back to 8.

 

[chillman88]

And that was exactly when I went hydroboost