JamesC

iTrader: (5)

Working on old cars is an adventure, isn't it (and not always a good one)?

JamesC

compuwiz1937

iTrader: (17)

Yeah, pretty much! The only good thing is that this is giving the paint on the sway bar more time to cure (I just used red Krylon, I'll probably get it powder coated when I have some money again) and I'll get to do the stop tests I wanted to do before I started on the car. Hopefully there won't be any more problems.

EDIT: I'd like to start shopping around for a posi carrier now to find out how much it'll cost. Can you tell me what I need to look for so I get the right thing? I've looked on eBay and seen some Auburn posis for around $300 but since I really don't know what axel spline I have and the measurement of the carrier and all that mess I really don't know exactly what I'm looking for. Hopefully I can find a deal on a carrier and I can sell this gov-loc unit, I saw one exactly the same as this one at $70+ on eBay, so I know I'll be able to make a little money back.

compuwiz1937

iTrader: (17)

It took a lot longer to swap out the damn studs that I thought it was going to take. Then I ****ed up 3 more lug nuts in the process and had to go buy more, and I also messed up another lug nut getting one of the wheels off because the socket was broken so now I gotta go get another one... Anyway after all the wasted time doing that me and my dad managed to get the old rear out and get the new one 90% in. All that's left is the sway bar and the brakes.

JamesC

iTrader: (5)

The rear end from an 84 would have had 26 spline axels. With 3.73's you have a series three carrier.

JamesC

compuwiz1937

iTrader: (17)

Thanks for that info.

We got the rear finished up this morning and replaced the front brakes and bled all 4 wheels. I broke in the pads and after that the car definately does stop better than before, and the squishing sound from the rear drums is also gone! I decided to "romp" on it from a stop (the rear tires actually squealed a little!) and I smelled something wierd when I stopped after I did that, I'm not sure what it was or if I was just smelling things, but I pulled in my driveway and went to check everything and it all looked good but I noticed the brakes are leaking a little at the splitter and maybe at the passenger side caliper. So I'm gonna check all that out tomarrow. Other than that little problem, so far I'm very happy! I'll get some pictures tomarrow when I have the wheel(s) back off.

compuwiz1937

iTrader: (17)

Tightened up all the brake lines and there doesn't appear to be any more brake leakage. I actually got to test them out today when some **** head pulled out in front of me and they are definately better than those damn drums. When I was test driving it the steering wheel started to shake a little again and wanted to pull to the right a little bit and I pulled over and checked everything but didn't see anything wrong and it stopped. I'll just have to keep an eye on everything for the next few days. Anyway here's the pictures I took this morning:





I love these 3.73 gears, they really don't make the car any faster when I'm already moving but they make a big difference from a stop. I can actually make the tires squal a little without power braking (and the one wheel peel is also gone because of the posi!).

On the issue of my speedo being off, if I bought the 145mph cluster for my car (and that's a big if since I have a 91), would the new speedo be right?

maroon88iroc

iTrader: (7)

no you need a new speedo gear in the transmission

compuwiz1937

iTrader: (17)

Dammit, I was hoping someone wouldn't say that. Please tell me it isn't too hard to change those?

Another axel question: I pulled a drum cover off my old rear end and it looks like the axels from that rear end could be used in the 84 rear end with the disk brakes. Could I use them if I wanted to? If so, wouldn't these axels be 28 spline (which would let me use a 4th gen carrier)?

JamesC

iTrader: (5)

No, the axels from your 91 are 28 spline while the 84 has 26. About the speedo. Sorry but I don't recall if you're running a T5 or a 700R4 and I don't recall the gear ratio of your old rear end.

JamesC

sofakingdom

iTrader: (1)

WRONG.

THe actual motion of the pointer is IDENTICAL regardless of the top speed. That is, if from 0-40 mph is 30° of travel on the 85 mph speedo, then it's 30° on the 145 mph one as well.

And of course, the universal constant for speedo calibration is the same too; 1000 revs of the cable = 1 mile.

So the speedo gears are always the same regardless of what range speedo you use.

I have a 145 mph one in my 83 car (formerly the stupid 2-handed pointer 85 mph thing).

maroon88iroc

iTrader: (7)

yes i know that but he has changed the rear end gear so the speedo gear in the transmission if its a 700r4 has to be changed to one compatable with the rear end gear he is running.

i have a quick question for you jamesC since you know alot about this stuff. are all 9 bolts posi carriers the gov lock system? b/c ive heard bad things about using that carrier with any kind of power. should i be concerned about using that if im putting out 400 hp at the flywheel?

compuwiz1937

iTrader: (17)

Sorry, I didn't expain that very well since I was in a rush. I meant to ask if I could use the 28 spline axels from my drum brake rear end in the 84 housing if I went with a "real" posi carrier from a 4th gen in place of the 84's gov-loc. Is 28 spline better than 26?

I've got a 700R4 and the original rear had 3.23 gears according to the RPO code.

EDIT: sogakingdom: I have a 91 so I have a 110 MPH speedo right now and a different cluster from 82-89. So for me to upgrade to the 145MPH speedo would probably cost $200+ since no one will let them go for any cheaper because that's around what they can get on eBay.

JamesC

iTrader: (5)

I can't imagine that all 9-bolts had the gov-loc, but I'd replace if yours does. It's pretty much crap.

JamesC

JamesC

iTrader: (5)

I believe you can, but I have no personal experience. The 28 is reported to be stronger.

You'll need to swap the driven gear to make your speedo read correctly.

The 82-89 cluster is cable-driven, the 91 electronic. The two clusters will not swap. You'll need a 90-92 cluster.

JamesC

compuwiz1937

iTrader: (17)

How hard is it to replace the driven gear?

I know about the cluster differences. I'd love a 145MPH speedo, but I don't know if I can spend the money for one.

krly79

I just did this swap about 6 month ago and your going to have problems with the brake line threads being different. Not a huge problem, but enough to p!ss me off. Also, I got mine out of an '84 Z28 HO and mine is a 3.23 rear, cause the car was an auto. 3.73's were manual rears. As for stopping, my drum rear stopped better than this disc rear, but that is the fact that the caliper design isn't that great and I do not have an ajustable proportioning valve. I swapped the master cylinder over off the '84 and I had problems with the threads again between the brake lines and the factory prop valve.

compuwiz1937

iTrader: (17)

I'm still using my 91 master and prop valve so I haven't had any problems with different size nuts.

I found out what was causing the smell and the steering veering. The ****ing passenger front caliper won't let off the brakes. I drove it again to today to see if it would happen again and it did and the car felt really slow and then I got a noticeable jerk in the steering wheel so I headed home immediately and jacked it up and the wheel won't turn! I got fan on it now to cool it off so I can take it off and make sure it wasn't just installed wrong since when it happened the first time it stopped after a little more driving (it being the smell and veering). x10000000000000000000000000000000

JamesC

iTrader: (5)

The hose(s) probably need replacement.

JamesC

compuwiz1937

iTrader: (17)

The hoses can cause that? I just bought new calipers for the front as well (only $9.88 each). I haven't tested them yet though.

compuwiz1937

iTrader: (17)

****. It still does it, the smell and heat aren't as bad but it's still noticeable. Guess I'll have to get the new lines.

Pat Hall

iTrader: (31)

As far as I know none of the nine bolt rears ever got the gov-lock. Every nine bolt posi unit I've seen has the cone clutch style posi, which isn't a great unit either, but it's way better than the gov-locks. Cone clutches wear out fairly often, but they don't explode like the gov-lock. Also, Compu-wiz will in fact have to change the drive gear on the transmission output shaft. Any ratio that's 3.42 or lower(numerically higher) requires the gray 15 tooth drive gear instead of the red 17 tooth gear they used with 3.23 and numerically lower ratios. This applies to the 700r4's anyway. I ran 3.42 in my car for a while and had to switch to the gray gear, then I went to 3.23 and had to change it back to the red gear again.

compuwiz1937

iTrader: (17)

Ok, but how hard is it to change them out? And more importantly, how much more is this going to cost me?

According to this site, it looks like I'm going to have to replace both gears, not just one: Speedometer Gears, Speedometer Gear, Ford, GM, Dodge 700R4 .

Pat Hall

iTrader: (31)

The cost is fairly negligible, maybe in the $20-$40 range. The driven gear is a piece of cake to change. The drive gear in the trans is a little more involved, but still not too bad to do. You have to remove the tailshaft housing (4 bolts), which involves removing the torque arm mount and the driveshaft. The hardest part for me when I did it was getting the gear retaining clip to release, but it's not rocket science. There's an article on the tech pages here that covers the procedure to replace 700r4 speedo gears. You might want to read through that, and maybe print it to take out in the garage with you when you go to do it.

compuwiz1937

iTrader: (17)

Ok, that doesn't seem incredibly difficult. The hard part I guess will be getting the car in the air. I didn't even think to look for a tech article for this. Thanks.

Just to be sure before I order, according to that site I posted above I need to buy the 15 tooth drive gear and the 43 tooth driven gear, correct?

compuwiz1937

iTrader: (17)

The rain finally quit today so I was able to take my car out and the passenger front brakes still smell a little, but the wheel was no hotter than the other wheels. It may just still smell because it hasn't had time to wear off yet. I think there's a brake fluid leak on that side so I'll get to check if the brakes are lock up on the rotor or not. Don't know if I'll do that or not today since the humidity is around 10000%.

compuwiz1937

iTrader: (17)

I believe my front brakes are ok now. I drove the car a lot yesterday and the smell from the passenger side seems to be going away slowly and I jacked it up today after I drove it pretty hard and the wheel spun pretty freely so I guess the new hoses fixed the problem. All that's left for now is the speedo gears.

Thanks to everyone who helped me with this.

maroon88iroc

iTrader: (7)

im going from drum to disc on my iroc can you elaborate on what needs to be done to the brake lines for the swap? also info on the e-brake cables as well.

looks like im going to be following your footsteps compuwiz this thread has helped me out alot btw.

compuwiz1937

iTrader: (17)

I can't help you on the different sized nuts since I kept my master and prop valve. However, the screw where the car connects to the rubber hose coming from the rear end matched up and I had no problems with that.

The e-brake cable swap is really easy. The cables just run from the calipers to the very back of the transmission hump and clip into brackets on each side and then the cables inside that actually do the work clip into this metal thing above the driveshaft that the e-brake handle is hooked to. It's pretty straight forward and there shouldn't be any surprises with that.

maroon88iroc

iTrader: (7)

alright good to hear. i am also keeping my master cylinder and proportioning valve for a little while at least but i wanted to be sure the brake lines off the disc brakes on this new rear would be the same as my drum setup is now.

JamesC

iTrader: (5)

The hard lines themselves, at least the driver's side, are different between drum and disc, but as Compuwiz mentions, it makes no difference because the line that joins the hard lines at the T is the same for both disc and drum.

JamesC

maroon88iroc

iTrader: (7)

i just picked mine up this morning and im going to strip it tomaro and im going to turn the rotors and get new pads and calipers. also im going to put new gear oil in it. what kind should i use? it is a g92 rear it has 3.45 gears and a n.o.s. posi unit in it. less than 1000 miles after rebuild and i only paid $200 for it i think i got a deal.

compuwiz1937

iTrader: (17)

I told Autozone the specs of the 84 and they told me exactly what weight oil I needed and how much I needed. I don't know if you caught it earlier in this thread, but I couldn't find a new gasket anywhere but Napa and JamesC said to get the limited slip diff fluid from a GM dealer.

$200 definately seems like a great price. I think after it was all said and done I ended up paying around $400 for everything I did, the brake stuff was the most expensive. The junk yard I got it from also had the audacity to charge me a damn core charge on the thing too (even though it was only $10.15)! Since this is just a regular rear end and it probably won't be really easy to sell, I think I'll take out the carrier and the axels and take off the sway bar and take mine back to them.