I have the very RARE opportunity to buy a complete 3.23 with POSI rear axle from someone in the UK. The unit is complete with rear disks and everything, I currently have rear drums

My questions are these;

1) How big a job is it to replace the whole unit?

2) What do I need to take (it's off a wrecker)

3) Will the disk brakes on the rear make a noticeable difference to my shabby offering at the moment (ie drums)

4) How the hell do I get this one past my wife? she's just about stopped freaking about the Lift bars and sfc's...

Appreciate your help from 'accross the pond'

Thanks

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'86 Iroc ZZ4
Best Run 13.8 @ 100mph
I told you to blow the bloody doors off!
The British Firebird/Camaro Site

 

If you use the search function at the top right of this webpage, you can find out the info on a bunch of the swaps we've done here... but to answer quickly:

1) Axle swap = easy, rebuilding the brakes = medium, bleeding the brakes = pain!

2) Depends on the years of the cars!! You might even need the prop-valve-to-rear-axle steel brake line. Let us know. At the least, I'd say get the axle, master cylinder, and proportioning valve. Grab the stuff now, we could always sort it out later- like you said, I don't imagine there's many f-bodies like that in the UK, someone might beat you to it.

3) They might, depends on if the rear discs work (look for "disc TSB" through search). Mine need to be fixed with the TSB parts, but if I hit the brakes really hard (panic stop!) I really feel a braking improvement- I wish I felt it all the time.

4) Disc brakes are safer, and will stop the car better after all your other mods! (Of course it might take a bit of fiddling to get them to work as brand new, but she doesn't have to know that!)


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

Hey Tom thanks for the reply, the 'donor' car is an '85 (only 32,000 miles) and mine is an '86... Should only just be run in I hope. Is the proportioning valve easy to grab? The guy is very helpfull, I just need to get a van or trailer now to pick it up.

It's costing me a fair bit, but going from 2.77 to 3.23 will hopefully be worth it alone?

Any other thoughts or advice.

Thanks again.

 

Yup, the prop valve is easy, it's under the master cylinder. When I pulled mine from the junkyard car, I used a rust-penetrant sprapy and a very large (thick jaws) adjustable wrench on the fittings. (My "special" flare-nut wrenches were ruining the nuts!) You will also need the master cylinder! You can find rebuild kits for cheap online. I think the '85 master cylinder will be aluminum like your '86 is... not that it matters, just a fact for fun!

I think you might be okay with the proportioning-valve-to-rear-axle steel brake line. (I'm now going to call this the "front-to-rear" line.) Check it out on both cars carefully. Here's the deal:

It seems that early 82-84 model f-bodies had the front-to-rear line go into the prop valve at the front of the valve. Seems that mid-80's front-to-rear lines go into the bottom of the valve. (The front-to-rear line is the largest fitting on the prop valve.)

My donor car was a 1984 TransAm. My car is a 1986 Firebird. My 1986 rear brake line would not meet up with the 1984's prop valve! I had two options:

1. Bend my '86 front-to-rear brake line to fit the prop valve - looked tricky, and the possibility of snapping it was a risk
2. Get the '84 front-to-rear brake line from the 84 car, and put it into my car.

I got the whole line from the '84 car. Just check out your car and the donor car's line and look for differences. Also, http://www.classictube.com sells the whole brake line kit- it's expensive, but at least there's an alternative out there.

You should also grab the rear emergency brake cables between the axle & adjuster.

I replaced my rear brake hoses with new ones, since it was a good safety idea. I don't know how online stores deal with the UK, but I bought a ton of stuff at http://www.carparts.com - if you go to a place like http://www.yahoo.com and search for "carparts.com coupon", sometimes you can find great deals for first-time buyers. I found a "$50 off of $100" coupon, and managed to buy $120 worth of brake/axle parts for $70. (I bought the e-brake cables, both rear hoses, new rear axle wheel bearings & seals, and a Bendix caliper hardware kit "H5611"- slides and bushings for BOTH calipers were inside!)


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

[This message has been edited by TomP (edited January 09, 2001).]

 

I did the same swap and DAMN!!!! Life was sooooo much better. Although I also noticed the posi too. But, rear discs are such a joy!!!!

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'82 Firebird, dead stock, 9 bolt disc rear, over 200,000 miles and still going strong, more to come...

 

Thanks for your time Tom, appreciate it.. I'll let you know how it goes, chances are I'll be getting my shop to do the whole thing, lack of a garage and the long winter evenings leave me little choice I think getting new lines as I go along will definately be a good idea.

Cheers

 

Just one other thing, will I have to recalibrate or change any gearing for the speedo?

 

Glad to help! Keep us posted on the swap!

If the axle has different gears inside than your stock one, then, yes... sorry, didn't think about that. The donor car's tranny should have the right stuff inside the tailshaft... I think there's two plastic gears you'll need, behind the speedo cable.



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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!