BretD 88GTA

I'm in the process of gathering the final parts I need for my front 1LE brake upgrade. I have an '88 Firebird GTA with the J65 disc/disc brakes.

As I understand it from AndyZ28, ebmiller88, and other sources that I need the #14089496 prop valve (which I just orderd from gmpartsdirect.com) AND the J50 Master Cylinder #18014286 which was used on the disc/drum cars.

However, gmpartsdirect.com DOES NOT list a master cylinder with part #18014286. Instead they show #18014287 for disc/disc cars (which is what I should already have) and #18060095 for disc/drum cars. The same is true for their 1989 and 1990 listing. 1991 & 1992 show the #18060095 master cylinder for all models.

I have also checked the master cylinder currently on my car and it has two numbers stamped into the bottom. The first is A50 and the second appears to be 18006814.

Okay gentlemen, let the debate begin. Anyone have any more details on this? I'm guessing that #18060095 is the "new" part number for the J50 master cylinder.

Thanks.

ANDYZ28

Two things to consider.

1) Your current M/C is nearly 15 years old.

2) You can get the correct M/C for early 1989 cars. J50 and J65 were the same. With such a very limited market, GM chose to simplify the aftermarket M/C selection, even in their own catalog. I have an early 1989 (new) J50 M/C on my 1LE equipped car. It works great.

Thanx,andyZ28

ebmiller88

iTrader: (7)

GM often replaces part numbers with updated ones or "service" numbers since the change. I'd just get the one for '90-'92 cars as all of these will be the same, either disc/disc or disc/drum cars.

I'd just go with the updated P/N master.

Ed

ANDYZ28

"I'd just get the one for '90-'92 cars as all of these will be the same, either disc/disc or disc/drum cars."

I don't think he can do that. He needs the one for the early '89 cars (1st design), I think.

Thanx, andyZ28

BretD 88GTA

Andy,
gmpartsdirect.com lists #18014287 as the M/C for 1984-1990 Firebirds with disc/disc and #18060095 as the M/C for the disc/drum cars. 1991 & 1992 shows #18060095 as the M/C for ALL models so that must be the M/C I need.

ANDYZ28

OK.

BretD 88GTA

After some more online searching I have found a couple sources that do list the #18014286 M/C. One of which is a Chevy dealership not far from me. Their price is $163. That's probably the route I'll go to be sure I'm getting the M/C I want.

james_85Z28

damn brett. I usually go to pep boys and get the $19.95 MC

ebmiller88

iTrader: (7)

Yeah, he should be fine with the master cylinder. Those should all have the same threads so it won't be an issue there, only with the prop valves.


Bret, call Dal at VanDevere Olds BEFORE you go out and pay $163 for a master cylinder, they can't be that much. I just got a used one off a drum car for $20, the only non-new part I used.

Ed

BretD 88GTA

James,
I'm still searching for better pricing. I have an e-mail in to Dal and am waiting for a reply. gmpartsdirect.com wants $124 plus their "shipping and handling" charge.

As for Pep Boys, there are certain parts I don't buy from them - starters, alternators, master cylinders, etc... - basically the "big ticket" parts. Too many bad experiences with their so-called rebuilds. IMHO, you get what you pay for and I always prefer to go with genuine GM units whenever possible.

BretD 88GTA

Okay gentlemen,
I have full clarifictaion on this. I ordered the J50 #18014286 M/C from Dal at VanDevere Olds and it arrived today. This is supposed to be the M/C used on the 1LE cars.

The GM part number on the invoice and box says #18060095 which matches what I found at gmpartsdirect.com. So, that is the new part number.

Now comes the pisser part - the number stamped into the bottom of the new M/C is A-50 18006814, which is IDENTICAL to the number stamped into the bottom of my current M/C on the car.

I have a sinking feeling I may discover the same thing with the prop. valve I bought.

I may keep the new M/C and install it since I've never relpaced the M/C on this car and I've owned it since the end of '93. For all I know, it's still the original M/C from the factory. But then again, I believe it may have been replaced at some point since it should have had the J65 M/C from the factory.

I guess I'll just chock it up to experience.

doc

OK, after 3 years of doing nothing about my 1LE brake update where I installed the SS Brakes kit and not an MC.

So, after all this time, i want to bring back this thread.

What MC part # do I buy today 3/4/2005 ?

And are the GM parts lighter (made of aluminum) and the aftermarket shops have cast iron or steel MCs?


Does it make any real difference to get a GM part or from AutoZone, PEP Boys, etc. ?

ebmiller88

iTrader: (7)

Just get one for a '90-92 as they're all the same. Unless you have to have a GM unit, any one from a parts store will do or get a used one. I paid $20 for my used one and it works great. Mine are both aluminum.

Ed

nortron

Hey guys, I have an 87 formula 350 w/42K miles on it and I'm finally going to upgrade the front brakes - either 1LE or aftermarket (Willwood). I see discussions here indicating that my factory master cylinder should be replaced with a 90-92 unit or the hard to find J50 #18060095 model. What is the reasoning behind switching the master cylinder? Is it a fluid displacement issue or larger booster or? Thanks for the info. Ron

M&M_GTA88

iTrader: (2)

Just to follow up on nortron's question above, does anyone know the reasoning behind switching the master cylinder out?

I have a '88 GTA that had disc/disc delco moraine brakes and I'm in the middle of the 1LE PBR upgrade for front and rear. Brakes are up and assembled, but I have two main questions before moving forward:

1. Do I need to change out the master cylinder?
2. Do I need to change out the proportioning/combination valve or can I just do the spring upgrade outlined here? https://www.thirdgen.org/forums/brak...e-upgrade.html

Thanks for the feedback!

M&M_GTA88

iTrader: (2)

Can anyone help with the above question?

Thanks,
Mike

sofakingdom

iTrader: (1)

Reason for changing out the MC and PV, is the different hydraulics at the wheels, have different fluid volume / pressure requirements.

Since there was NEVER a combination of the PBR fronts and Saginaw rears available from the factory, and the Saggy rears have CONSIDERABLY different hydraulic characteristics from any of the other brakes, there is AFAIK no factory MC that's actually "right" for that combo, though maybe some are less bad than others.

OTOH the properties of drums and PBR rears are so similar that in at least some of the years of PBRs, the MC and PV were the same in both of those systems.

Given how crappy the Saggy rears are in a general overall way, how poorly they work even at their best compared to other systems, and how mismatched they are to upgraded fronts, it doesn't seem like "A Good Idea" to upgrade the fronts, and leave those on the rears as-is.

Note that in that other post in the link, the instructions apply to an 89 car, which would have come with PBR rears, not Saginaw. Therefore if you get the PV for a (I think) 91-92 car, which would be the one that covers both drums AND PBRs, you should be able to apply that mod to your system, if your car needs it. Can't say for sure whether it will or not. The LS1 system has hydraulic characteristics that are different again from the older fronts. It's also not impossible that the MC & PV for a LS1 car might be just about right for your setup.