few days ago i came across a 9 bolt posi rear on craigs list.

the owner said it came out of a 87 iroc z28

are there any good things about this rear??
vs my 10 bolt open rear.
aside from mine being open and having an extra bolt...

im sorry for the noob questions but civics dont have rear ends so im new to it.

another thing is that, do i need a special "adjustable" brake proportioning valve?

according to some one i know he said that i need that if im installing a posi rear.

this rear has disc brakesertyuiop instead of drum brakes which is what my car has.

aside from the parking brake cables.. is there anything else that i need to modify or replace?

the trans torque arm.. if thats what you call it.
(the bar that connects the trans to the rear end)

can i re-use my old one??

thanks for all your help.

 

Well first of all welcome to the world of muscle cars. The 9 bolt rear ends are marginally stronger then the 10 bolts how ever they are by no means indestructable. Upgraded from an open diff to a limited slip will make both tires burn off the line. Thus drastically increasing the traction off the line and making the car more fun to drive. All the stock suspension will bolt up to the 9 bolt. The proportioning valve is a good idea but not necessary. The bias on the factory proportioning valve is optimized for the flow requirements of the wheel cylinders. So to get the full potential out of the new discs were you to install them an adjustable proportioning valve would be necessary. On an end note I wouldn't swap to the 9 bolt they were only used in limited numbers and parts are extremely expensive for them. You would be better off looking for a used after market rear or just beefing up the 10 bolt you already have. I didn't see anything in the post about what your end goal is for the car and that will determine your optimum rear setup. Hope this atleast points you in the right direction

 

as far as the installation questions if everything bolts up its cool for me.
the reason i bought it was because i didnt think that for 150$ it was THAT bad of a deal.

my goal for this car is to have a fast fun car with an extra tire of traction, and disc brakes.

its not a drag car.. its my daily driver , i just want to have a fun car that packs a punch.

thanks for the help.

and thanks for not bashin on me for being an import lover

 

A proportioning valve from a car originally equipped with rear discs would be a good idea. The concept that you need an adjustable proportioning valve because you're installing a posi is nothing short of ridiculous--one has nothing to do with the other.

JamesC

 

thank you will36, jamesc for the info. i will be swapping it in today.
hopefully all goes as planned. (majority of the time it doesnt lol!)
but with minor set backs ill have it in today.

ill try and take lots of pics and possibly do a write up

thanks again.
this forum rocks!!

 

It also would be a good idea to get the 9-bolt parking brake cables because they are different from the 10-bolt.

 

yep . i knew that the parking brake cables for the drum setup would be completely different.

so since i work part time at an auto part store. i ordered up left and right side. wagner parking brake cables.
the one thing i did not check on is if the front parking brake cable is the same.

the part that goes to the handle. but im sure it should be the same.
all i need now is some rear rotors and pads. and hopefully the calipers are in working order haha.

 

b4 you buy it find out what gear is in it. certain gears use the 2series carrier and others use the 3 series carrier. if it has the 2 series it isnt worth the trouble.

 

Your stock rear might have 3.23 or 3.45 and the 9 bolt might have a 2.77. That's good for gas milage but not for acceleration.

 

Any 9-bolt is a better rear on a daily driver.

 

I agree to that. But, if he ever plans on swapping gears, it will be just another expense to add on top of the gear set. 9bolt.com is selling used 3series carriers for 350+50shipping, and then 225 for the gears. He might be able to find a better deal on ebay. but wht take the chance. I learned this lesson from experience. Fortunatly I got lucky on ebay and found the carrier and gear iwanted for 150

 

Why so?

JamesC

 

ok i have an update.
every thing was going as planned.
until i went to tighten the driveshaft bolts.....

i snapped one in the yoke

now my question is .. can i use the yoke from the 10 bolt?
to swap over??
or should i just drill and tap it???

 

Your better off taking the bolt out if you can, there are tools for that.

 

try a left handed drill bit first, alot of times they will spin right out

 

You should be able to, the pinion spline did not change betwen the 9 & 10-bolts.
----------

I thought you had more knowlegege then to ask that question about the strength of BW 9-bolt.

 

Strength, yes, I understand, but IMO strength has little to do with daily driving--or perhaps, my opinion is biased by the sedate, senior citizen fashion in which I putt around .

JamesC

 

eh i figured ill just try and drill and tap the bolt.

i have 1 half of the rear connected. so ill have to jack up the car as high up as i can. and remove the driveshaft from the trans. so i can work underneath the car. sigh... if i cant save it to be the same 7/16 bolt. then i have to find another thread size and pitch with a small hex head since clearances are tight because of the u-joint caps.( if thats what you call them)

ok well im off to drill and tap..

 

Nine bolts are significantly (my opinion) stronger and safer then 10 bolts when it comes to drag racing. If an axle brakes on a 10 bolt it can slide out and damage the car if you still have drum brakes. The nine bolt axle is contained at the ends and it will not slide out if you snap and axle. As far as strength is concerned, I have drag raced my nine bolt with drag radials and 5000 RPM launches 100's of times and never broke anything.

The bottom line is I have watched many f-bodies at the strip break 10 bolt rear ends but I have never seen a nine bolt break and I beat on mine very hard.

 

oh my goodness.......

i decided to run a tap through the remaining threads of the yoke.
ran through 2 of them. and the last one. ****ING THING SNAPS!!!!!!
OMFG!!!!!!!!!!!!!!
wtf!! this has NEVER happened to me. a freakin TAP snap inside the bolt hole!!!!

i have NO drill bits that can drill through the tap... i am absolutely stumped...
some one help... im honestly just about to take off that yoke and swap it with the one on my 10 bolt..
if ppl here say they didnt change the number of splines. and they are interchangeable then ill do it unless some one else has a better idea? some one help lol

 

UPDATE:

i couldnt get the tap out of the bolt hole.
so idecided to take off the yoke off the 10 bolt rear.
i took off the yoke for the 9 bolt rear.
splines are identical.
the 10 bolt fits in the pinion of the 9 bolt.
but the thickness of the metal where the splines are, are different for the both.

the 9 bolt yoke is thicker which when it is installed the pinion seal sits tightly around the yoke.

with the 10 bolt. there is about 1/4 of an inch in gap and the seal does nothing. therefore if i were to install it. the fluid would **** out of that 1/4 inch gap.

so now i have to find a 9 bolt yoke somewhere.
my job can get one but it will have to be shipped UPS.
which will be about 2 days.
so , whatever.

i expected something like this because it was wayyy to good to be true that this thing was gonna go perfect without problems for only 150 dollars. lol

 

Does anyone know where to get the Axle bearing retainers for the 9 bolts? I am having a bitch of a time getting them. From what I understand is that when they are installed they stretch to ensure a tight fit therefore not to be re-installed as they are already worn. Is there a rebuild kit that contains them? I am certain that someone has to have these stupid things as you need to remove them to change your axle bearings.

 

Oh ma....You shoulda just gotten a reverse thread tap to get that broken bolt out. Drill & tap woulda be more work. How tight did you try to tighten the bolts?

If you don't know 110% how to set up a ring & pinion, your gonna tear the gears up & be putting your 10-bolt back in next weekend.

 

well i know its not the best method. but i do it all the time when i replace pinion seals.

take a chisle. and bang a slit on the pinion shaft where the threads are at the very tip of the pinion.
and just slide the chisle down to the nut and bang a small slit in the nut.
so you have two lines , one on the pinion and 1 on the nut. which would mark its original position once i installed the nut back on. i hit it with my air gun and slightly hit the trigger until i saw the two lines that i made line up.
after i found out that the 10 bolt yoke was not going to work.
i managed to extract the bolt and the tap out. and safely chased all the threads on the 9 bolt yoke.
so all is good and dandy.
the only thing that is left is the brake job. got rained on so ill finish that up tomorrow.

i got some pics for yall
later on

 

On the old 9bolt.com site their used to be an article stating that the 9 bolt rears are stronger than the dana 44 rears and can handle up to 500hp stock with an automatic, not sure about torque or witha manual trans.