Horntoad
Newbie
Firstly, I know brakes have been discussed a lot. And I’ve read a bunch and forgotten half of that. Want to see if I’ve got some of this straight and ask a question or two. Thanks for any more patience and time you have for this topic.
I’ve got a 1995 5.7L 2DR 4WD Tahoe LS. It came with JB5 brakes.
I’ve added the 3.15” front calipers and have (but have not yet installed) 11.15-inch x 2.75-inch duo-servo rear drums with the GM 1721425 wheel cylinder. Those 3.15”calipers are traditional (non-low drag), correct?
1. Did the Z56/9C1/Z60 Tahoes with the 11.15” drums use a 1” or 1 3/16” wheel cylinder; I’ve seen conflicting info (unusual to come across conflicting into on the web, I know)? Which part number? What about the JB6/JD6; what rear wheel cylinder did they use with the 11.15” drums? Is it accurate that both the Z56/9C1/Z60 and JB6/JD6 Tahoes had the 1” rear drum wheel cylinder?
*It can’t be as simple as there being of GM book that I’m missing that has model year RPOs and their corresponding parts?*
**My master cylinder is leaking.** I know I could rebuild it, but thinking I'd rather swap it out.
From what I’ve read it seems, to best match the brakes, I should go with the 1.25” bore master cylinder out of the police/limited. I’m looking to go with combos GM used, if possible.
2. Is it accurate that there is no difference (other than the reservoir and need for an adapter) between the GMT400 and GMT800 1.25” bore master cylinders?
3. But the 1.25” bore “police” (9C1/Z56) master cylinder came with QTU (quick take up) that is not functional; Is that a correct statement? Can the same be said of the “identical” GMT800 1.25” master cylinder?
But I’ve seen where some say the GMT800 was designed for disc/disc whereas the GMT400 for disc/drum. Would it also be accurate to say that some GMT800s with 1.25” master had disc/drum?
4. If the GMT400 and GMT800 1.25” master cylinder are in fact identical, other than larger, different style reservoir, and if it is true that both were designed for/installed in disc/drum setups by GM, any reason I would not use the GMT800 version?
5. Which master cylinder is the best match for a 1995 5.7L 2DR 4WD (disc/drum) Tahoe LS with 3.15” piston front calipers and 11.15-inch x 2.75-inch duo-servo rear drums with the GM 1721425 wheel cylinder? Is it the 1.25" bore master cylinder, and does it make any difference if I get the GMT400 or GMT800 1.25" master cylinder? Do I have the right/best match wheel cylinder and is it, in fact, a 1” bore?
I’ve got a 1995 5.7L 2DR 4WD Tahoe LS. It came with JB5 brakes.
I’ve added the 3.15” front calipers and have (but have not yet installed) 11.15-inch x 2.75-inch duo-servo rear drums with the GM 1721425 wheel cylinder. Those 3.15”calipers are traditional (non-low drag), correct?
1. Did the Z56/9C1/Z60 Tahoes with the 11.15” drums use a 1” or 1 3/16” wheel cylinder; I’ve seen conflicting info (unusual to come across conflicting into on the web, I know)? Which part number? What about the JB6/JD6; what rear wheel cylinder did they use with the 11.15” drums? Is it accurate that both the Z56/9C1/Z60 and JB6/JD6 Tahoes had the 1” rear drum wheel cylinder?
*It can’t be as simple as there being of GM book that I’m missing that has model year RPOs and their corresponding parts?*
**My master cylinder is leaking.** I know I could rebuild it, but thinking I'd rather swap it out.
From what I’ve read it seems, to best match the brakes, I should go with the 1.25” bore master cylinder out of the police/limited. I’m looking to go with combos GM used, if possible.
2. Is it accurate that there is no difference (other than the reservoir and need for an adapter) between the GMT400 and GMT800 1.25” bore master cylinders?
3. But the 1.25” bore “police” (9C1/Z56) master cylinder came with QTU (quick take up) that is not functional; Is that a correct statement? Can the same be said of the “identical” GMT800 1.25” master cylinder?
But I’ve seen where some say the GMT800 was designed for disc/disc whereas the GMT400 for disc/drum. Would it also be accurate to say that some GMT800s with 1.25” master had disc/drum?
4. If the GMT400 and GMT800 1.25” master cylinder are in fact identical, other than larger, different style reservoir, and if it is true that both were designed for/installed in disc/drum setups by GM, any reason I would not use the GMT800 version?
5. Which master cylinder is the best match for a 1995 5.7L 2DR 4WD (disc/drum) Tahoe LS with 3.15” piston front calipers and 11.15-inch x 2.75-inch duo-servo rear drums with the GM 1721425 wheel cylinder? Is it the 1.25" bore master cylinder, and does it make any difference if I get the GMT400 or GMT800 1.25" master cylinder? Do I have the right/best match wheel cylinder and is it, in fact, a 1” bore?