7.3 IDI Turbo Knock -> Engine Pull and Rebuild

MICHAEL MICHAUD

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Alright gentleman. I found the vacuum leak. A tiny hose on the passenger side was disconnected. My brakes work now but only shortly if I press the brake 2x rapidly forget it. Vacuum pressure from the pump is 25 in hg very quickly. Can I just connect the pump right to the booster?

The check valve works.

I can bet how amazing it is to swit h to hydro but I dont have the time or resources right now.
 

MICHAEL MICHAUD

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Great. Ill sort out HVAC some other time when i have more of it If i cant figure out what the deal is with whatever is leaking.

I have a 5 speed and plenty of clothes and windows to control the climate. Ill need that defroster comin up here soon.

Ordered a new shifter boot because mine has been smashed to smitherines.

Just wish I could get the brake assist more consitent. I am definitely going to switch to hydro boost by next year
 

laserjock

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Tester controls just default to defrost with no vacuum so it’s not completely a loss. Stopping is pretty important. I think I’d try connecting directly since you are 5 spd. Really can’t hurt. Just not heat control or cruise control.
 

MICHAEL MICHAUD

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Tester controls just default to defrost with no vacuum so it’s not completely a loss. Stopping is pretty important. I think I’d try connecting directly since you are 5 spd. Really can’t hurt. Just not heat control or cruise control.

Thats great news, thank you!

Each line and component holds pressure great only thing i didnt test is this little guy that I broke. When i run the truck and read vacuum at the booster its 18 instead of 25 so somewhere in between I lose about 7 in hg. Ill cap off all the outlets and test one at a time. Worst case senario I rtvd the check valve and ill run vacuum straight to it.

What is this guys. I broked it being rough. Its like a vacuum bus or something.is this the sensor that kicks the brake light on?

Pretty sure my dash is busted alot of the indicator lights dont work but that doesnt really bother me too much.


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laserjock

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That’s the brake warning sensor. If the thing beside it is your vacuum manifold and it has those open spots, I think you found your issue. There is also a coffee can looking resovoir that is prone to the bottom rusting out. Usually it’s on the driver inner fender.
 

Thewespaul

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Coffee can is only on the brick and bull trucks iirc. Could be your booster is leaking behind the master cylinder, you can test the booster with a vacuum gauge to see if it is leaking
 

genscripter

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I've had 3 vac pumps go out on me in the many years of owning an IDI. Each time, I didn't find out until I was hundreds of miles from home and my brake assist stopped working.

I tried to replace my tuna-can vac sensor (you took a picture of it), but that didn't fix my warning light. So I did the next best thing. On that vacuum hub tree, I spliced into it and installed an old mechanical boost gauge that had positive and negative pressure. Now I have a realtime reading of my vac pressure on the dash, just in case I ever have a vac leak or vac pump failure in the future.
 

genscripter

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The vac pressure is just nice to know. Most vac leaks are slow progression. So over weeks, it'll degrade and you'll know in advance to check things out. Unlike the idiot light, which tells you when it's too late.

Also, it's interesting to see the vacuum pressure change at higher altitudes. Due to the relative decrease in pressure, the vacuum pressure reading can increase quite a bit. Once I got up to 12,100 ft elevation, and the vac pressure reading approached 15 inhg.
 

IDIBRONCO

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The vac pressure is just nice to know. Most vac leaks are slow progression. So over weeks, it'll degrade and you'll know in advance to check things out. Unlike the idiot light, which tells you when it's too late.
I LOVE the vacuum gauge that I installed in my truck a couple of weeks ago and will never run an IDI without one now. I feel that it's that important.
 

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