Hydroboost - Hard Pedal

[MrMarty51]

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The front and rear reservoir are swapped size wise, but if they are plumbed right its not a big deal.
The reservoir is bigger than the one on my dads truck

So I suppose bore maybe..?>

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I do not know what the internal differences between the two types is, I have never dismantled either one to find out.
The parts man at that store is a very good friend and had worked as a parts man at one of the local GM dealerships for many years.
With My phone call He investigated what had been sold to that character and what part number was on the box, when the MC in the box got to Him, He checked and while on the ohone with Me declared that the MC that had gone out of the store was for a vacuum assist and the proper MC for that application was in Billings and would be in store the next day.
Thats about all I know about the differences between the two, maybe one digit in the part numbers ?

 

[Scottgenex]

Thanks for those diagrams. For some reason my search didn't pop up anything worth looking at, or they were super blurry and I couldn't zoom in. It does look like I could have the low pressure lines swapped on the respective PS return ports. Not sure that it makes a difference, but hey, it's a freebie fix just to see.

As for the MC, I purchased the replacement based off the vehicle I pulled it off, an 84 diesel truck with JD7 brakes. My rear drums are 13" so all should match up and be happy from my knowledge. It's plumbed as - front larger resvoir for the front discs; rear res for the rear. Verified when I was bleeding the whole system.

 

[AuroraGirl]

Thanks for those diagrams. For some reason my search didn't pop up anything worth looking at, or they were super blurry and I couldn't zoom in. It does look like I could have the low pressure lines swapped on the respective PS return ports. Not sure that it makes a difference, but hey, it's a freebie fix just to see.

As for the MC, I purchased the replacement based off the vehicle I pulled it off, an 84 diesel truck with JD7 brakes. My rear drums are 13" so all should match up and be happy from my knowledge. It's plumbed as - front larger resvoir for the front discs; rear res for the rear. Verified when I was bleeding the whole system.

i noticed your combination valve switch isnt hooked up, maybe your only using your front or rear brakes because its tripped

 

[AuroraGirl]

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