Has anyone here done a big front brake swap, (1LE, LS1, etc.), while retaining rear drums? I know many have done it while retaining rear Delco 10.5" discs.

 

The drums will go eventually, but there still back there and work just fine. Have 98+'s on the front and difference is more than noticeable. Not Brembo great, but still far and away better. Pull the trigger and get em. You know you want to

 

So you've got LS1's up front and drums in back?

Seems to me that the rear drums work just as well or even better than the trouble prone Delco rear discs.

 

Probably better. They easily stop the rear axles from rotating at idle with the tires in the air.

I put C4 standard duty (12" X .81" rotor) fronts on and retained the rear drums.

RBob.

 

Everybody complains about the Delco calipers, but mine easily stop the rears at idle (car jacked up off the ground) & have even locked them up at 65mph! I know locked up is not the best braking method, but it does mean that they can clamp tight for sure. The visual aspect of the small rotors under my 17" wheels are what bug me about them.

 

I replaced the front brakes on my 92 vert with LS1 brakes last year. They really improved the braking and no problem with locking up both front and back. I've already started this Winters project to replace the rear end and update to rear disc brakes. I'm doing the brake upgrade for a couple of reasons... Reduce brake fade and improve the appearance.
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The stock 16" Iroc wheels really look great in front with red PC calipers and I really want the the same look in the back.

 

Looks good!. No issues with the braided steel lines?

 

No issues with the braided stainless steel lines. I modified the bracket that held the old brake lines to the shock so it holds the new brake lines in place and everything stays clear of the wheel.

 

Is this with the stock combo valve? That is where the real issue is, not enough line pressure to the rears with the stock and operational combo valve.

RBob.

 

Stock as far as I can tell. I just know it is the same way as I bought it in & I didn't change anything about it.

 

If it's any help, I believe that the rear drum combo valve and 1LE combo valve are the same.

 

I currently have the 13" C5 front brakes and a set of stock drums on the rear while I rebuild my disc brake rear. I havent had any issues running them together. I do believe that the valves are different in that the rear disc valve has a higher line pressure. There is a thread on hear on how to upgrade the spring on a drum prop valve to get the higher psi.

 

I plan to change out the combo valve to the correct disc/disc combo valve for correct pressure to the rears. Although I've read about changing the spring in the combo valve also works I prefer to replace my disc/drum valve with a stock disc/disc combo valve.

 

Different part numbers for drum and 1LE disc (note below). The info below may be generally interesting:

In searching I've found that 89-91 shows the same Cylinder, Brk Master GM 18014286. Earlier years show different masters for J50 and J65. GM, however, pretty much made them interchangeable (All have the 'quick take up' master):

https://www.thirdgen.org/forums/susp...fferences.html

There are different combination valves (if only one was needed, why would GM design valves for different applications?). For exampe:

Valve, Brk Combo (1989 2nd Des) (J50) (1990 [and also 91]) (J41, J42) GM 10136839
J41 - BRAKE SYSTEM, POWER, FRONT DISK, REAR DRUM, CAST IRON
J42 - BRAKE SYSTEM, POWER, FRONT DISK, REAR DRUM, ALUMINUM

Valve, Brk Combo (1989 1st Des) (J65, 1LE, Y82) GM 14089496
J65- BRAKE SYSTEM, POWER, FRONT & REAR DISK
1LE - PERFORMANCE PACKAGE, SHOWROOM STOCK RACING
Y82 - MERCHANDISED PACKAGE, FORMULA

JamesC