- Thread starter
- #41
Interesting article, I'm hoping my pump has already been modified. I'll call them Monday.
Let's talk about Hydroboost Brakes (1 Viewer)
- Thread starter scrapdaddy
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- Thread starter
- #42
I'm guessing you wouldn't want to buy a master cylinder with ABS braking capabilities.
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The pressure relief in my pump (off a 2500 that had hydroboost) was already 5/32 just for reference, although it would be super easy to drill yourself.
I bought two hydroboosts off 2500’s at the junkyard for $30 each.. I only had to the buy the second one because I dropped the first one off the workbench and snapped the pedal rod out of it, luckily that was the one with the bad accumulator.
Make sure the master cylinder you choose will work with the hydroboost, there are differences between the vacuum and hydroboost master cylinders, specifically the diameter of the protrusion on the back of the master cylinder that indexes into the hydroboost housing.
I bought two hydroboosts off 2500’s at the junkyard for $30 each.. I only had to the buy the second one because I dropped the first one off the workbench and snapped the pedal rod out of it, luckily that was the one with the bad accumulator.
Make sure the master cylinder you choose will work with the hydroboost, there are differences between the vacuum and hydroboost master cylinders, specifically the diameter of the protrusion on the back of the master cylinder that indexes into the hydroboost housing.
- Thread starter
- #45
This is why I'm thinking like Megadoomer and buy everything for the same vehicle, less chance of me messing up.
Good to meet you today. Brought this thread up so you could see the list of parts. Post 44
- Thread starter
- #47
Yeah, it was a good day! Thanks for bringing this up, I'll stop by Napa and see what they pull up.
RUSH55
SILVER Star
Was looking at a 1994(?) C3500(?)
that we have at work today, with a TBI 454 (7.6L {?}). Was checking out the serpentine belt setup and noticed the hydroboost. Pretty clean setup. Never even noticed it before and I’ve been driving that old POS for like 6 or 7 years!
that we have at work today, with a TBI 454 (7.6L {?}). Was checking out the serpentine belt setup and noticed the hydroboost. Pretty clean setup. Never even noticed it before and I’ve been driving that old POS for like 6 or 7 years!
- Thread starter
- #49
How do the brakes work on that old POS?
What do you need/want?
- Thread starter
- #51
A brand new OEM Chevy hydroboost and master for the same vehicle, aka 2500 pickup, etc. I'd rather not buy a used system or rebulit either. The Chevy dealer by me needs a VIN number to order or look up parts. I haven't gotten serious yet, this will be a Winter project.
RUSH55
SILVER Star
The brakes on the front like to lock up a bunch, but it does have a 500 gallon diesel fuel tank sitting on the rear.
What size pistons do you have in your calipers?
- Thread starter
- #54
J Mack, I have no idea, they are 95 4 Runner calipers and rotors. The back are 2007 4 Runner calipers and rotors.
So do you know if you have less piston surface area on the rear calipers then the fronts?
- Thread starter
- #56
Poking around on the enterwebs it looks like they're 46mm. I believe them to be the same front and rear.
Less than ideal.
I would square that away first before I went down the Hydro boost road.
- Thread starter
- #58
Please explain, seems ok for toyota to use on the 4runners.
If the front and rear calipers are exactly the same “Brake Balance” or “Brake Bias” would be extremely difficult to achieve,
Not a great article but it explains a bit about the differences between the front and rear brakes without going into a bunch of race car technology.
Front Brakes vs Rear Brakes: What's the Difference?
I looked up 95 4 Runner “Front” calipers.
Casting S12WF had 4 EA 43mm pistons
Casting S13WM had 4 EA 45mm pistons
So let’s assume you have one of those.
Do you know if you’re using front or rear 2007 4 runner caliper in the rear of your pig?
2007 4 Runner “Front” calipers.
Casting 13WM had 4 EA 45.5mm pistons and will look similar to your fronts.
2007 4 Runner "Rear" calipers have a single 45.5 piston and should look similar to the one below.
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- Thread starter
- #60
OK, I see what you're getting at. Yes the rears are single piston and the front is dual piston.
