Rear drum master cylinder on J65 4 wheel discs?
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Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
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Axle/Gears: BW 3.45
Rear drum master cylinder on J65 4 wheel discs?
I was doing a search on 1LE brakes and I ran across a GM service bulletin about the early J65, 10.5" 4 wheel disc brakes. It stated that if customers complained about the J65 pedal feel, that the dealer should replace the master cylinder with the one for rear drums.
Anyone know anything about that?
Anyone know anything about that?
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Car: 1989 IROC-Z. Original owner
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Re: Rear drum master cylinder on J65 4 wheel discs?
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Car: 1982 Z28
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Re: Rear drum master cylinder on J65 4 wheel discs?
I was running 1LE fronts and J65 iron-caliper rears, switched to the drum master cyl as the tech bulletin described. Noticeably less pedal effort to haul the car down than with the J65 master cylinder, and no way I'd swap back. Highly recommended.
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Car: 1989 IROC-Z. Original owner
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Axle/Gears: BW 3.45
Re: Rear drum master cylinder on J65 4 wheel discs?
BTW, were you happy with the 1LE front/J65 rear combo?
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Re: Rear drum master cylinder on J65 4 wheel discs?
When I converted, I, too, swapped in the J50 master (along with the correct combination valve) as the 1LE conversion suggests. I don't recall the pedal feeling different, though I did this several years ago. I've since thrown on the so-called 1LE rears. The system is very nice.
JamesC
JamesC
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Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
Transmission: World Class T-5
Axle/Gears: BW 3.45
Re: Rear drum master cylinder on J65 4 wheel discs?
When I converted, I, too, swapped in the J50 master (along with the correct combination valve) as the 1LE conversion suggests. I don't recall the pedal feeling different, though I did this several years ago. I've since thrown on the so-called 1LE rears. The system is very nice.
JamesC
JamesC
I've also ordered the ANDYZ28 CD on the subject, to see what he's got to say. Hope it's 30 bucks well spent.
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Re: Rear drum master cylinder on J65 4 wheel discs?
I used Andy's CD way back when. If you haven't seen the following link, it might prove useful as well:
http://web.archive.org/web/200605221.../1LEbrake.html
JamesC
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Car: 1989 IROC-Z. Original owner
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Transmission: World Class T-5
Axle/Gears: BW 3.45
Re: Rear drum master cylinder on J65 4 wheel discs?
Enough so that I'd recommend the swap (besides I'm **** enough to like the front and rear calipers to match )
I used Andy's CD way back when. If you haven't seen the following link, it might prove useful as well:
http://web.archive.org/web/200605221.../1LEbrake.html
JamesC
I used Andy's CD way back when. If you haven't seen the following link, it might prove useful as well:
http://web.archive.org/web/200605221.../1LEbrake.html
JamesC
On my '83, I think I want to go with the cheap man's braking improvement route. Maybe, braided lines for the front, and the aforementioned J50 MC. We'll see....
Weird that the one I'm willing to spend all the money on, ALREADY brakes pretty darned good, now that I've replaced the original Gatorbacks with Goodyear F1's.
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Car: 1982 Z28
Engine: LS1
Transmission: T56
Re: Rear drum master cylinder on J65 4 wheel discs?
They were very good for street/commuting use, but durability on road course track days was limited.
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Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
Transmission: World Class T-5
Axle/Gears: BW 3.45
Re: Rear drum master cylinder on J65 4 wheel discs?
Enough so that I'd recommend the swap (besides I'm **** enough to like the front and rear calipers to match )
I used Andy's CD way back when. If you haven't seen the following link, it might prove useful as well:
http://web.archive.org/web/200605221.../1LEbrake.html
JamesC
I used Andy's CD way back when. If you haven't seen the following link, it might prove useful as well:
http://web.archive.org/web/200605221.../1LEbrake.html
JamesC
Okay, here's the big question. Should I do it myself? This is kind of new ground for me. I've never removed and replaced a spindle for example. It looks fairly straight forward. Was it an easy swap? How much time do you think it took you to swap to 1LE front brakes? Any tips?
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Re: Rear drum master cylinder on J65 4 wheel discs?
Okay, here's the big question. Should I do it myself? This is kind of new ground for me. I've never removed and replaced a spindle for example. It looks fairly straight forward. Was it an easy swap? How much time do you think it took you to swap to 1LE front brakes? Any tips?
JamesC
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Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
Transmission: World Class T-5
Axle/Gears: BW 3.45
Re: Rear drum master cylinder on J65 4 wheel discs?
Yes, do it yourself. At the time, I'd never removed a spindle either and certainly never modified one, but it is, as you say, fairly straightforward. Easy? Well, spring removal/replacement can be dangerous. Time? Depends on how fast you work and how many obstacles you run into--for example the a-arm bolts, one or more, are likely seized to their metal sleeves. Two were in my car. They required an hour or so a piece with plenty of sweating, beating, yanking and cursing (done in French, of course, since it sounds much more dignified). Tips? If you're considering lowering the car, now's the time; now's also the time for struts and/or strut mounts as well as new bushings for the a-arms. Work slowly and carefully. The job isn't rocket science.
JamesC
JamesC
BTW, I usually curse at my cars in Greek. It seems like I'm getting my point across to them better.
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Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
Transmission: World Class T-5
Axle/Gears: BW 3.45
Re: Rear drum master cylinder on J65 4 wheel discs?
Okay James, one more question and I'll leave you alone (for now). Is it better to fully assemble everything before you put it on the car, or is it better to install the spindle and then assemble the brakes?
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Re: Rear drum master cylinder on J65 4 wheel discs?
JamesC
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Car: 1982 Z28
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Re: Rear drum master cylinder on J65 4 wheel discs?
I'm much happier assembling the components onto the car, one at a time, tightening using an accurate torque wrench and Loctite red formula.
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