Rear end swap questions - Which way to go?

[DerekTheGreat]

Hi all,

I'd like to do the disc/posi swap for my '88 (Got stuck backing in my driveway for the last time!!) but it seems more complicated than the swap I did with the Firebird, which was aquire a posi unit with discs from an '83 pacecar T/A & bolt up and connect the rubber hose to the T on the diff.

I read through this:
http://www.grandmarq.net/vb/showthre...Disc-Rear-Swap
And it caused me to be uneasy & reconsider the swap, perhaps I should just pay to have a posi swapped in my current rear end and deal with the drummies? I don't relish the idea of having to swap over the master, worry about the proporting valve & booster although my biggest concern is with the e brake & rear lines, a dude mentioned having to flare the lines to match but another said he swapped just the rear over & all was well (John I think?) Anyway, the shop that swapped the Firebird's axle quoted me at $610 to swap in a new trak lok & $350 to swap an axle over. I ended up paying close to $800 though with the bird because I had the axle stripped, painted and they replaced a few bearings inside.

What say you guys? Am I overthinking the problem? Should I just swap the non posi carrier for one that is? Are disc brakes that much better back there or can similar stopping power be had with the later MC & booster? Disc rears on the bird made a huge difference...
I'm not sure how to go so your thoughts and comments would be appreciated!

Derek

[ootdega]

I myself decided to stick with the drums until I have everything I need for both front and rear disk conversion.

I got myself a 28-spline Trac-lok for the 8.8 on Ebay for around $120, and it was around $40 to install it. Trac-loks for the 31-spline (the one with disks) are almost three times that much. It works great, no problems whatsoever.

I'd say it's a good idea to stick with what you have for now, even put some money into the drums if they're starting to go out. It's a good investment and they'll last you fine until you can do what you plan on doing the way you want to do it. I laid down $800 for a full brake job and they work better than the disks on my mom's Chevy.

[mcninetyone]

I pulled a complete rear, 3:55 gears with disc and posi from the JY. (low miles car).
Bolted the whole thing in and never looked back, no booster or master swap.
Everything works just fine, no problems, and it does stop much better.
I did have to make some small adjustments to the rear brake lines, but not a big deal.
There is nothing to fear with this swap.

[87gtVIC]

I have the stock rear with a trac loc, 3.73's and discs. If I were to do it again I would swap in the newer rear end for the added track width. I did not need to change any booster or master out as everything work great on my 87 stock stuff. I did need to use some sort of brake line adapter to adapt the stock lines to the newer rubber lines for the calipers.

[pantera77]

If your going to be swapping rear ends personally I'd go with a 90+, the extra width is nice.
The rear disc do work fine with the factory master and proportioning valve, but it's not perfect, and it always seemed silly to me to do a swap to improve your cars braking performance, and then not have them functioning at 100%.

Then again I'm one of the few who think with properly adjusted drums these cars stop just fine. 11" drums are a direct bolt on, and I'd wager on a DD there just as good as the measly 92-02 rear disc.

[DerekTheGreat]

Thanks for all of the replies guys!

87gtVIC & mcninetyone:
So the 92-97 rear is a bit wider than stock? By how much? Is it noticeable? As for the brakes, I've been down to adjust the drums but never paid attention to the main line supplying the tee. I assume there is a tee on the diff right? So the problem is the stock rubber line's end fitting doesn't match up to the newer tee? Is this adaptor easy to find?

ootdega:
It is really tempting to just deal with the drummies and pay to have the carrier swapped over.. Did you have the stopping bits at all four corners replaced or did you pay $800 to have the rear dealt with? I had some work done to my car and I mistakenly said, "Replace stuff that looks bad" without mentioning "Ill do the brakes myself." They put new pads (unknown kind, probably semi metallic) & hoses in but kept the old calipers, oh, they also put new wheel cylinders out back. Well, I put new rotors, bearings, calipers, ceramic pads & rubber hoses + adjusted the drums on Ashley's 89 and man, what a difference that made. The pedal effort is nowhere near where mine is, even after all the work that they did to it. Car stops so nicely and feels "modern." Makes me wonder if its the ceramic pads or new calipers causing the nice feel with her 89. The MC & booster look to be the same between both cars, they are aren't they? I've got my rears adjusted and stuff but again, the pedal feel sucks. Not spongy or anything, but because of that I'm thinking I'll just go to a yard and yank the newer style MC & booster (That link I copied claims better pedal feel from those bits) & possibly the rear end. You guys have more experience than me though. Pulling a rear right now being witch titty cold isn't as enticing as say, the couch with Diablo III and hot pizza...

Pantera: 11 inch drums are a direct bolt on ye say? Do I need to swap the wheel cylinders? I'm ok with bigger drums really, I just thought perhaps I'd get better pedal feel out of the discs since what I've got now is fairly lame. I've got a 1969 Fury III with manual drums at all four corners. Stops fine if you stand on it, just can't get the fronts to stop making noise, sounds like a damn big rig when I stop
Derek

[miamibob]

Unless one does "spirited driving" I have found the stock set up works just fine. But that's my judgment....

[DerekTheGreat]

Stock does do the job but here in Detroit we've got drivers who shouldn't be driving, traffic that suddenly stops when it shouldn't and people who like go cross the road when they shouldn't. I just want a bit more reserve and better pedal feel. Ashley's '89 is just fine. Mine is slightly different.

[87gtVIC]

Thanks for all of the replies guys!

87gtVIC & mcninetyone:
So the 92-97 rear is a bit wider than stock? By how much? Is it noticeable? As for the brakes, I've been down to adjust the drums but never paid attention to the main line supplying the tee. I assume there is a tee on the diff right? So the problem is the stock rubber line's end fitting doesn't match up to the newer tee? Is this adaptor easy to find?

The specifics are laid out somewhere on the forum regarding the track widths. Stock the rear wheels are in too much. Switching to the newer rears helps make things look less goofy.

Again I added discs to my existing 87 rear end. I had to get adapters to adapt the stock hard brake lines on the axle to the rubber lines feeding the calipers. I used the same adapter that people use to make the big brakes work up front. No idea on the size but it is around in a sticky somewhere. A fellow forum member was able to find them easily for me. I did have trouble finding them but may not have been looking for them in the correct places.


Also To pull the rear from a yard Id just bring a cordless sazwall and cut the control arms.

[DerekTheGreat]

The specifics are laid out somewhere on the forum regarding the track widths. Stock the rear wheels are in too much. Switching to the newer rears helps make things look less goofy.

Again I added discs to my existing 87 rear end. I had to get adapters to adapt the stock hard brake lines on the axle to the rubber lines feeding the calipers. I used the same adapter that people use to make the big brakes work up front. No idea on the size but it is around in a sticky somewhere. A fellow forum member was able to find them easily for me. I did have trouble finding them but may not have been looking for them in the correct places.


Also To pull the rear from a yard Id just bring a cordless sazwall and cut the control arms.

Oh, I thought you may have added them but I wasn't sure. Sawzall, I'll add that to my list of tools I need. I haven't flared brake lines in over ten hears, so glad I don't have to do that.

[mcninetyone]

What I did was take a complete disc brake rear with 3:55's and posi from a 92 CV.
And I bolted that in place of my drum brake, 2:73 open rear.
I used all the rear brake lines from the 92. ( rear door back).
Front brake lines and such are still stock box.
I'm using my original booster and MC.
Some day I may change out the booster/MC, but right now everything, including the e-brake is working just fine.
And I've got no problem leaving it "as is"
I'm, sure I could do this, that and the other thing and it make it even better.
But I'm not sure it would be worth it.
This is a very easy swap.

[ootdega]

ootdega:
It is really tempting to just deal with the drummies and pay to have the carrier swapped over.. Did you have the stopping bits at all four corners replaced or did you pay $800 to have the rear dealt with? I had some work done to my car and I mistakenly said, "Replace stuff that looks bad" without mentioning "Ill do the brakes myself." They put new pads (unknown kind, probably semi metallic) & hoses in but kept the old calipers, oh, they also put new wheel cylinders out back. Well, I put new rotors, bearings, calipers, ceramic pads & rubber hoses + adjusted the drums on Ashley's 89 and man, what a difference that made. The pedal effort is nowhere near where mine is, even after all the work that they did to it. Car stops so nicely and feels "modern." Makes me wonder if its the ceramic pads or new calipers causing the nice feel with her 89. The MC & booster look to be the same between both cars, they are aren't they? I've got my rears adjusted and stuff but again, the pedal feel sucks. Not spongy or anything, but because of that I'm thinking I'll just go to a yard and yank the newer style MC & booster (That link I copied claims better pedal feel from those bits) & possibly the rear end. You guys have more experience than me though. Pulling a rear right now being witch titty cold isn't as enticing as say, the couch with Diablo III and hot pizza...

Pantera: 11 inch drums are a direct bolt on ye say? Do I need to swap the wheel cylinders? I'm ok with bigger drums really, I just thought perhaps I'd get better pedal feel out of the discs since what I've got now is fairly lame. I've got a 1969 Fury III with manual drums at all four corners. Stops fine if you stand on it, just can't get the fronts to stop making noise, sounds like a damn big rig when I stop
Derek

The $800 was for all four corners. Rotors, calipers, pads, bearings, everything. I've never needed to floor them, I can stop really quickly without slamming my head into the steering wheel in the process. Very confident braking. I have to be careful when they're wet or they try to fling me through the windshield.

[jaywish]

When you keep a car for a long time you tend to notice repeat part failures. Doing the big front swap ended the warped rotor problem for me. My home town is very hilly so tough on brakes. After I did the fronts the 10" rear drums could not keep up with the fronts. The rear disks work just fine with the upgraded fronts.

[VicCrownVic]

Stock does do the job but here in Detroit we've got drivers who shouldn't be driving, traffic that suddenly stops when it shouldn't and people who like go cross the road when they shouldn't...

Yes, yes, and yes.
Also people cross wherever they want. Jaywalking... what's that?

It's kind of like playing frogger when driving in and around Detroit only in this version the cars are trying to avoid everything.

[DerekTheGreat]

What I did was take a complete disc brake rear with 3:55's and posi from a 92 CV.
And I bolted that in place of my drum brake, 2:73 open rear.
I used all the rear brake lines from the 92. ( rear door back).
Front brake lines and such are still stock box.
I'm using my original booster and MC.
Some day I may change out the booster/MC, but right now everything, including the e-brake is working just fine.
And I've got no problem leaving it "as is"
I'm, sure I could do this, that and the other thing and it make it even better.
But I'm not sure it would be worth it.
This is a very easy swap.

That's great to hear, so you were able to use the original e-brake cable too then? Did you notice the difference in axle width? As long as it doesn't make the car look goofy I might be all for that, as it now sounds like an easy swap just like my Firebird was. If you went to a bone yard, what did you pay for the axle? Just trying to figure out how much I'm going to spend. Being Michigan they have a love affair with salt so that means I'll probably want to get the axle cleaned up, need new metal lines, rubber lines and while I'm there I might as well toss calipers, rotors & pads at it too.

The $800 was for all four corners. Rotors, calipers, pads, bearings, everything. I've never needed to floor them, I can stop really quickly without slamming my head into the steering wheel in the process. Very confident braking. I have to be careful when they're wet or they try to fling me through the windshield.

11 inch drummies would probably add the extra oomph I need too. Decisions, decisions.

When you keep a car for a long time you tend to notice repeat part failures. Doing the big front swap ended the warped rotor problem for me. My home town is very hilly so tough on brakes. After I did the fronts the 10" rear drums could not keep up with the fronts. The rear disks work just fine with the upgraded fronts.

Sounds like the front swap is a lot more work than the rear. Good thing most roads are flat around here but that's one reason I love drivng a stick, engine braking. I have yet to warp a set of rotors though, everyone else I know does it once a year or so.

Yes, yes, and yes.
Also people cross wherever they want. Jaywalking... what's that?

It's kind of like playing frogger when driving in and around Detroit only in this version the cars are trying to avoid everything.

Haha yeah, everything, including gaping holes in the pavement, downed power lines & the occasional mattress or two. Had a dude blitz across the street at night in a powered wheeled chair the other day, no reflectors, all black too. Not like there was anyone behind me but waiting and not being selfish isn't their game, had to swerve to miss that one. Business as usual in Detroit