These are the only pictures I have right now, I'll try and get a picture of the metal tab with the numbers and stuff on it when I figure out where I'm going to put this thing. It's out of an 84 Z28, looked like it was a really nice car back in the day (white, tan interior, 4 wheel disk, 5.0 HO, ERS sound). I shoulda grabbed the vin and I think the RPO codes went with whoever took the center console. Anyway, I turned both rotors and they both turn (they're a little rusty, you can't see it in the pictures) and moved the u-joint and when I could get to the u-joint I turned it and both rotors turned so I assumed the gears were ok. Pretty clean bor being out of an 84 all things considered. The rotors might need to be replaced since I didn't have any fancy stuff to keep them from hitting the ground I had to use old wheels and tires I found.











Can anyone tell what exactly this is from these pictures? It looks like there won't be too much of a problem installing since this rear end only needs one brake line running to the back like my drums, the only problem might be the e-brake, will I be able to hook my drum cable to the disks?

 

If the rear is from an HO car, it should have 3.73's. Typical 10 bolt with 10.5 rotors and miserable old iron calipers. You might consider swapping them for PBR's or, at the very least, looking into the "fix it" kit for these calipers. Try a for more info about the latter. The e-brake cable for rear discs is available from automotive stores, such as Autozone.

JamesC

 

Alright, I'll need to find out what my V6 has and see how much the speedo will be off. Since you seem to know what you're talking about, if this is the 3.73 rear end is it posi-trac?

Since these are the iron calipers, are they still better than my current drums?

 

You'll have to pop the diff cover to verify (you should change the fluid anyway). Yes, IMO, the rear discs will be better--and you'll have an easier platform to swap on bigger brakes at some point.

JamesC

 

Yeah, I definately want to change the fluid and make sure there are no shavings in it. I guess I should also probably get a new seal too right? As long as the disks are better, that's what I want for now. I wanted this rear end because it's somewhat rare, it's upgradeable, I want better stopping power, and if I get new wheels disks all the way around will look better. I'm going to try and get it out of the truck today and hose it off and get all the dirt and fluids off and see if I can read that tab.

Since I may also paint it before I put it in and I may see about changing out the bushings for the sway bar (I'm glad I didn't feel like taking it off, I didn't realize it until I got home but that one is a lot thicker than mine) and control arms (if I decide to use them, I need to look and see if these are beefier than the ones on my car now or not) since they squeak a little, unless WD-40 or something will take care of that.

EDIT: I just looked through my RPO codes and saw that I have the GU5 so my car should have 3.23 ratio. Is this 3.73 ratio going to be better for my car? Do you know how much the speedo will be off?

 

Alright, well unless there's another tag somewhere I haven't seen yet, the one I was talking about says use limited slip diff lube only.

 

Open the case up and see what it has. Could be a Gov-Lock, which is better than an open rear, but not a performance piece. Grab some 80-90 weight gear oil, some LSD fluild and a gasket, should run you less than $10 at your local parts store. The 3.73's will make you v6 seem faster and it should be worth a tenth or two in the quarter.

 

I will open it up after I clean it up real well and take a few pictures since once I get it open I doubt I will have a clue what the hell it is. The only part I'm most worried about is the brakes, I had no way to test them before I broke the line (before the screw in for the rear end BTW) since I was by myself. What would the gear oil be for (like I said, I don't know jack about rear ends).

Questions about the e-brake: will I be replacing the entire e-brake cables with the parts from Autozone? Should I tell them I need the disk cables for an 84 or a 91 or does it not matter?

And how do I get the damn clipers off? I don't see how I would do it (unless whatever it is is covered by brake dust caked up on the back).

I hope all these questions don't seem stupid, I just don't want to **** anything up.

 

Got it on jackstands and got some new pictures.

Driver side:



Pass. side:





10 Bolts:



Is this the drain plug?



What is the second thing on the brake calipers? Should I avoid getting water in them when I go to try and clean this thing?




EDIT: I covered up those things on the calipers in question with duct tape and started to hose it down and it looks like it's in better shape than I thought! Most of its dirt and came off pretty easily with just a hose. I'm gonna load it into a trailer and take it up to a car wash and blast it with a pressure washer and degreaser. I may not even have to paint it now.

 

That's actually your fill plug in the one picture. To drain it, you just undo the ten bolts and pull off the rear cover. The "things" that you duct taped on the calipers are the brake bleeder valves.

 

The fill plug is on the bottom? Then what's this I uncovered at the car wash?



The pressure washer worked really well, there's still a some dirt that I think I can get off with a wire brush but just about all of the grease build up is gone on the diff and the back of the brakes. I covered it with engine degreaser and then blasted it with the high pressure soap and then water. I also got all the rock parts out of the rotor except for one rock that a little deep in the hole. I might take a few more pictures tomarrow in the daylight.

Oh, and when I take the diff cover off and put it back on does it have to be torqued a certain amount? I don't have a torque wrench and the one my dad had broke. How much fluid do I need to buy to fill it up? I might open it up tomarrow.

 

Ask for the 84.

 

Vent.

If you're going to continue to work on cars (and it's addictive, isn't it?), I suggest you buy a manual. All you questions can be easily answered there.

JamesC

 

Tech problems.

 

Double tech problems.

 

I had completely forgotten about the Haynes manual I have that my uncle gave me from his Camaro. I looked and it does have all the torque specs, so I guess I need to get a torque wrench. The car wash did get a good bit off, but I missed some spots on the bottom. I decided that I'm going to try and paint it anyway, I want it to look nice. As long as the rotors aren't damaged, those will be cheap to get refinished (or whatever the real name for it is, I forget) and I think I'll get the ceramic low-dust pads form Autozone. I'm also going to get new hardware for the sway bar and paint that as well.

When I was looking through the manual, I saw a list of rear end codes but the only number I could find on mine was C(or 6 not sure)273

I called Autozone and asked about the e-brake cables and they said there wasn't a listing for that.

 

Ah, . Any self-respecting automotive store should be able to provide you with the cables (Just ask for cables for an 84 Camaro with rear discs).

JamesC

 

That's what I thought! I just went up there to get the stuff to change the fluid and they don't have the seal either (and can't order it)! Pep boys said they had something under the name of brake cables but it didn't say e-brake cables and they would have had to order it.

Autozone nor Advance Auto could get me a rear diff seal either. But I found it on Napa's web site: http://www.napaonline.com/masterpage...et+-+Rear+Axle Hopefully they have it in the store. I also found the parking brake cables on Napa, but damn they're expensive! $26.49 for the right and $32.49 for the left! I knew I should have tried to get the cables off the car I got the rear end off of.


Before I go spending all this money on stuff, let me ask you this: providing the gears inside this thing are good as well as the rotors, do you think I got a good price for $85?

EDIT: I called Autozone back and asked for parking brake cables instead of e-brake cables and whoever I talked to was able to find them that way. They're $15.99 and $16.99. That's a little more reasonable!

 

All you really need to seal the rear cover is to put about an 1/8" thick bead of rtv all the way around the sealing surface and bolt it on. I haven't actually bought a gasket to seal a rear cover up in years now. They seal just fine with rtv. You're supposed to torque the cover bolts to about 25 ft. lbs., but you don't have to actually use a torque wrench. It's not that critical. As long as you get the bolts good and snug, they'll be fine. Don't forget to pick up a tube of limited slip differential additive while you're at the parts store. As far as filling it, they usually take about 2 quarts. If you buy 3 you'll have enough for sure. The way you fill it is you want the rear axle as level as possible, then you just pump the gear lube in until it starts to trickle back out of the fill hole and you're there.

 

Oh, so the LSD isn't it's own bottle? It's something I add to it. Ok I didn't know that. Now I really know what I'm looking for and why Gladstoneiroc said I needed gear oil! This service manual didn't say that, just how do chane it.

Thanks for that tip as well, if Napa will have to order the seal, I'll get some of that silicone to seal it instead.

Tomarrow I'm gonna get the sway bar off so I can sit it level on the jack stands and flip it over to clean the bottom. I'll probably do the fluid swap tomarrow since I'm not buying any of the bushings or any of that stuff until I make sure this is a good part. I'll let ya'll know how it goes.

One more quick question about the fluid change, the repair manual said to wipe everything down that I could with a lint free towel, is that really necessary?

 

The price is right, IMO. As long as the mating surfaces are clean, you'll be good to go. I'd use GM limited slip additive. Couple of things to consider: Check for oil leakage around the insides of the rotors and axel flanges. If it's there, you may need new seals. While the diff cover is off, check the ring and pinon for the numbers 41 and 11, which will verify that you have 3.73's (though you should if the rear actually came from an HO car).

JamesC

 

Alright, would I need to go to a dealer for GM's additive?

I haven't taken the calipers or rotors off yet, but when I do I'm going to be checking everything that needs to be checked. I'll make sure there's grease in it, that the bearings are good, etc. Though if there was any oil behind the rotors its probably gone now since I washed it at the car wash. I'll be cleaning everything and checking everything before this goes anywhere near my car. By the time I'm done with it, this thing will probably look to nice to put under the car.

I didn't notice anything in the service manual yet, but is there a way to check the calipers to make sure they work properly without having them hooked up to a car?

 

Yes, to the additive. You might consider simply buying new calipers (they're very cheap) to avoid possible problems.

JamesC

 

Damn, that was the most expensive $10 I ever spent! I bought two quarts of Valvoline Durablend 80W-90 gear oil for $12, the gasket for $6, and the LSD additive for $9.

I have actually thought about buying new calipers but I won't be able to spend any more money.

After lunch I'll get started on the fluid change.

 

Well, I got side tracked and starting cleaning on this thing some more with a wire wheel. I did just the diff housing and I finally got the cover off 10 minutes ago. I didn't see any shavings in the fluid (it was really dark), there was some small crap that looked like dirt, but I'm pretty sure that came from the diff cover. It looks like this thing was serviced at some point before bcause of the orange stuff used in place of the gasket. All the gears look good. Here's the pics:

 

When I was trying to scrape the old seal off the cover, I noticed a magnet that had some shavings on it. Is this bad? Should I just leave it or try and get them off? I did wipe down the inside of the cover with a shop towel (not the magnet though) after I took this picture since I left it sitting inside up.

 

The mag is doing its job. Clean it as best you can and forget it.

JamesC

 

Good, that's exactly what I thought and did. Looks like I'll be adding the fluid in the dark anyway. I guess I'll go ahead and order the POR-15 kit too.

I think I found out that this is a Positrac rear end and it is the gov-loc version, is that right?

EDIT: Guess I'll be waiting until tomarrow for the fluid. It got to dark. Oh, and I did find the 41 and 11 you were talking about on the gears inside so it is a 3.73.

 

You've got a Gov-Lock, which as is better than a open, but not competive with a later auburn, torsen, or aftermarket lsd. If you are careful it will last and be useful.

 

Since it came out of a 305 car, I imagine it should handle anything my V6 can manage to throw at it. So what's good about it and what's bad about it? Are there any options for upgrades later on?

Will threadlock be necessary on any of these bolts/screws?

 

On the diff cover, no.

JamesC

 

Also you will want to change the brake hose.I would change the brake hose also.If you can afford to go to braided line(do a search for member ebmiller on here).Since you've cleaned the axle tubes look on the passenger side tubeon the pinion side for the axle code.It's a series of letters and number stamped into the tube.Now with age and rust may have made the unreadable but you may get lucky.

 

Any reason I'll need new brake lines? Wouldn't the braded lines only make a difference if I replaced all the lines up to the master cylinder? I don't know if you can tell in the new pictures since the old line cleaned up pretty well with water, someone had the driver side line coming off that splitter replaced sometime recently. I did put tape over the end so crap couldn't get in there.

I was looking for the number earlier but I couldn't find it. I'm going to clean up the axel tubes some more with the wire wheel today and see if I can find it. I'll also probably get the rotors off and take them to Pep Boys and make sure they're ok and get them refinished. I also need to get the diameter of the sway bar so I can order the new hardware for it.

JamesC, wouldn't I only need that valve you were talking about in the other thread if I needed two brake lines to the back? Since this one came with that splitter from the factory it looks like, I shouldn't need that right?

 

Your old rubber ones are around 22 years old. Good time to replace. The braided hose is the one with the yellow tag:

https://www.thirdgen.org/forums/atta...s-89-rline.jpg

Spohn Performance, Inc.

The rubber version of the above will be considerably cheaper.

Yes, you'll need the valve. Go look under your hood at the old valve for a comparison.

JamesC

 

Ohh, I thought you were talking about replacing all the lines not just the rubber ones. On thing about that though, when the driver side line was replaced, they took that rubber part out. Should I just leave it and replace the rubber from the splitter to the car and on the passenger side or should I try and "fix" it?

Do you know where I can get good part numbers for the prop valve? I looked at that page you posted in the other thread and got called a dealer and they said that number wasn't a part number and he couldn't look up the part without a VIN. I gave them the number for the 90-92 one by the way.

If I did go and the get new calipers from Autozone, they should be the fixed ones right?

Here's my valve.

 

The driver's side was/is originally a hardline; it hasn't been replaced with rubber.

IIRC, the part numbers there are for the PBR set-up. Won't really help you. You need a stock prop valve and master for a four-wheel disc car with the J65 option, 82-88. GM should still have that. If not, hit the bone yards; these should be plentiful.

They're fixed. Again just ask for rear calipers for an 84 with rear discs (the J65 option).

JamesC

 

Yeah, that's what I asked for when I was at Autozone. After the core charge return they were only $43 a piece I believe. Depending on how much the prop valve costs, I may go ahead and do that now. Then I won't have to bother cleaning them.

I'll PM ebmiller88 right now, maybe he'll have the e-brake cables too.

 

I don't know if you missed my edit or not. Please check.

JamesC

 

My master won't work either?

 

Sorry about the confusion; the other link started off about PBR's, which are a different breed of cat. Personally, I'd replace both. That said, check this link (where GM essentially says the master from a drum car is good to go on a disc car:

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

JamesC

 

Just entertain me on this one, what would happen if I just hooked up the brake line and bled the brakes and didn't replace the master or prop valve?

Is my booster fine at least?

 

Check what flyitlikustolit says in the other link:

https://www.thirdgen.org/forums/tran...rear-swap.html

JamesC

 

I forgot about that post. So basically I'll lose some potential braking power in the rear by keeping my master and prop valve? What about if I kept my master and just replaced the prop valve?

 

That's my guess, but fly doesn't seem to think that it's a problem and his car apparently stops very well--I have no personal experience.

According to GM, that's doable.

JamesC

 

I guess I'll decide what to do after I do the swap and see how good they are. I'm going to do some brake tests before and after. I'm going to pump the brakes so they don't lock up and then I'm going to lock it up from 30mph or so.

On a side note, my power seat track finally showed up!!

 

Damn I'm pissed. I was turning the thing on jack stands to have it sitting flat (as if it was in a car) to make sure it wouldn't leak and there was a box on one side and I didn't noticed until it was to late but the box was in the way of the shock mount and pushed the damn thing on the jack stand. It looked like everything was ok though, luckily I had the jack stands as low as they could go in case something like this happened. I didn't get anything done on the rear end yesterday except getting the fluid in since I was working on putting my power seat in. After I get a few other things done today, I'll drag it out and pull one of the calipers and rotors (maybe both) and probably do some more wire wheel work.

My POR kit will be here tomarrow, so it'll be painted soon I hope.

I think I'll definately be getting new calipers, I just found them for $25 after the core charge return at Advance Auto.

 

I took the calipers and rotors off today (that was not nearly as the repair manual made it out to be). Not too dirty back there all things considered.





I got the rotors turned and they're both fine thickness wise and neither are warped.



I'll take a wire wheel to the top of the center but I'll use sandpaper on the sides so the surface doesn't get messed up. If I had thought before hand, I would have brought sandpaper and sanded it while it was spinning on the machine.

 

I got it 98% of it painted today, I didn't think that little 4 oz. can would be enough but the phrase a little goes a long way definately applies here. The only parts I haven't painted are where the ropes I was using to hold it up were and the u-joint.

One question about painting the u-joint, is it ok to paint all of it or should I avoid painting the part where the driveshaft connects?

 

Well I'm swapping in the rear end today! Pics later.

 

Or not. Turns out 3 of the damn wheel studs had ****ed up thread and I also ****ed up one of my lug nuts because I forced it on of thread trying to see if it would work. So I had to go to a dealer to get a new lug nut and then I went and bought 10 new studs. Luckily I didn't take anything off of my car except one wheel. So maybe tomarrow.