Jump to content

Sign in to follow this  
johnbell47

Bent pinion flange R-180

Recommended Posts

I need to buy a pinion flange for a R-180. '74 260 Z. Mine is somehow bent which causes a heck of a shake in the driveline. Good used would be great! Thanks!

Share this post


Link to post
Share on other sites

Do you have any experience working on diffs. Changing a pinion flange seems easy, but getting bearing pre-load right is not as easy as poeple think on used bearings.

You could be fixing a vibration and getting a whining diff in return.

It might be easier getting a complete diff.

FWIW

Chas

Share this post


Link to post
Share on other sites

you are of course correct. But what is to say that the complete diff won't also whine? The bearing preload procedure is in the FSM, which I have and have read, Doesn't seem too complicated to me. Or is it

?

Share this post


Link to post
Share on other sites

Here is a R180 in League City near Houston. Would be a drive to get it but would probably be cheaper than having it shipped. Plus you would get to inspect it in person as it does look pretty dirty in the picture.

Datsun 240z r180 rear end

Share this post


Link to post
Share on other sites

your location in reguard to N.E. Texas etc. oops! see that you are in the bay area. how much for just the flange and to ship.??

Edited by johnbell47
error

Share this post


Link to post
Share on other sites
your location in reguard to N.E. Texas etc. oops! see that you are in the bay area. how much for just the flange and to ship.??

I assume this is in response to my post? I don't know if I want to remove the flange because without it the diff is probably totally worthless. I don't know if I could give it away. I'll think about it... ;)

Share this post


Link to post
Share on other sites

Depends how much it is bent, but why don't you remove the flange and have someone with a lathe take a skim off the face. A very simple operation, and i doubt that it would weaken it. No need to take the diff out of the car.

I would machine up a tight fitting mandrel in the lathe,to spin the pinion on. You will see at a glance how much it is bent, and if the mandrel is a good tight fit in the flange, a series of light cuts can be performed on the flange. If you really want to get fancy you can thread the end of the mandrel, and put on a nut to hold the flange.

Share this post


Link to post
Share on other sites
you are of course correct. But what is to say that the complete diff won't also whine? The bearing preload procedure is in the FSM, which I have and have read, Doesn't seem too complicated to me. Or is it

?

FWIW I have changed pinion oil seals on diffs and had mixed results. Whining is a problem and often happens after the pinion re-aligns with the crown wheel. I only had sucess when I did NOT set the pre-load to factory spec. The old bearings are worn and the pinion/crown position is worn to suite. Pre-loading the used pinion bearings will shift the alignment and can cause it to whine.

My advice: Note the position of the pinion nut and then remove it. Check that the pinion flange freely moves up & down on the splines. Remove any lock tab burrs on the nut so it will turn freely. Tighten it the original position and check the tension with a tension wrench. It will be a lot less than factory spec.

Fit the new flange and pinion seal and use this tension to pre-load the new flange.

Its not perfect, but it worked better than factory spec.

Chas

Share this post


Link to post
Share on other sites

I just read a post from jmortensen, that these differentials did not have crush sleeves for pinion preload, he was saying that he just set his 1/2 impact gun to the middle setting and hammered it on.

Share this post


Link to post
Share on other sites

The factory service manual corroborates jmortensen's statement. The bearing preload is adjusted by selecting spacers and shims, not by crushing a corrugated spacer. Reomving and replacing the companion flange should not change the pinion bearing preload or the pinion height.

We changed the companion flange on the STi LSD we have in our Z and there is no apparent gear whine.

Share this post


Link to post
Share on other sites

I think that Eurodat was just pointing out the possibility of a whine. No guarantees that a simple flange swap will be easy and fix the problem without creating a new one. It seems to be that some people work on their diffs and end up with a whiner and others don't. But no guaranteed way to fix the whine if you get it.

Nobody has asked how the flange could possibly get bent? It's pretty stout and would be surprising to have enough force to bend it without damaging something else. Are you sure it's bent, or could you just have internal damage or a bad bearing causing a pinion shaft wobble? You might be just wasting time with a flange swap.

Share this post


Link to post
Share on other sites

I have hunted this problem for over a year, did all the things that you do, U joint angles, balance the shaft, twice, etc. etc. I found the vibration by putting the car up on six jack stands, taking off the wheels and firing that baybie up, 5th gear, idle screw set to 80 mph,(this is when the vibration gets really bad) then crawling under with a stethoscope. when I touched the nose of the diff it liked to have knocked the ears off my head! this pretty much isolated the vibe to that area. The dial indicator told the rest of the story, I figured the pinion shaft was bent, as the indicator on the flange indicated twenty thousands out, but when I removed the flange and put the indicator on the shaft, it was perfect. that's when we went to the drive shaft shop, chucked it up in a lathe and checked the runout. it is thirty at the front of the flange and was in fact 20 where I checked it. So, the machinist verified what I had found. How did the flange get bent, I don't know. It was bent when I bought the car I guess. Could be the 400 horse 350 and a hard launch, could have been a U joint turned loose 30 years ago and banged the dang thing, I just don't know. There has been a lot of speculation among those that have looked at it, but nothing that I definitive.

Share this post


Link to post
Share on other sites

One thing I wondered about that you might answer. The Nissan flange is difficult to find, the Subie flange is out there all over the place, My drive shaft is 1310 U joints with an adapter to the Nissan flange. there is probably an adapter from the 1310 joint to the subie flange available, but I wonder, would the late model subie flange fit the old Datsun pinion shaft? The Subie flange looks to be a lot stouter!

Share this post


Link to post
Share on other sites

We were able to swap the companion flange from our 73 240Z R180 to a 2006 Subaru STi R180 without any issue. Based soley on this I will yes, you should be able to use a Subaru flange.

Edited by beermanpete

Share this post


Link to post
Share on other sites

Is the spline count on the axles, the same? Is it possible to just buy a 2004 Subi rear and bolt it up? I hate to be so stupid by my brain is swimming with all the info out there. I have, basically a street machine, it is a boulevard cruiser, So I am interested in reliability, I have a tuned down 350 which is plenty of power for me, air conditioning, lots of sound dreading material, quiet exhaust, etc. What I want to know is can I actually swap out a diff that is 30 years newer, get a gear ratio that works better with my T-5 overdrive transmission for a hell of a lot less money? really?

Share this post


Link to post
Share on other sites

Nope, axle splines are different. It's a damn shame.

Beta Motorsports makes a stub axle with subaru splines though, looks like wolf creek is selling them now. $500, but I guess that's still probably cheaper than hunting down an OS Giken LSD.

Tranny & Rear Diff Parts

Edit: Or you can have custom axles made.

Share this post


Link to post
Share on other sites

I finally fixed the vibration. I was unable to find just a pinion flange and had to buy a complete 3rd member. I changed the flange, didn't fix the vibration, then I noticed that the driveshaft had the paint worn off the slip flange about 1/2 inch rearward from where it goes into the transmission, then I got to looking and the moustache bar was in contact with the down braces for the rear of the A arms. I had built a Ron Tyler mount according to the specs that I got I know not where, but the dang thing moved the 3rd member back. I put the factory mount back on and reworked the Tyler mount to be just a snubber to prevent the front of the diff from moving. Basically I sandwiched the diff between the factory mount and a modified GM transmission mount, I shaved about 3/4 inch off the G.M. Mount eliminating the single bolt on top. now we just have a rubber block with a two bolt mounting flange, I compressed this about 1/8 inch with the front crossmember. That moved the vibration rearward. I did not have the half shafts on so it had to be the rear end. I took a chance and mounted the junk rear end that I had bought to get its flange and that was the problem. No more vibration. I cannot see anything in the bad rear that would make it vibrate, but there is something wrong in there. this car is smooth as silk up to 95. It has never been right, but I just did not know what "right" was. With the Hushmat, quiet mufflers, mild 350 chev, stock rubber suspention all new. new KyB struts, air conditioning that works pretty good, all new rubber window and door seals, Mid line Sony sound with component speakers and Lexus Mirrors,Honda wiper motor with working washers, working rear window heater, flashers, seat belt warning chime, etc. I believe this baby is ready to drive just about anywhere in comfort.

Share this post


Link to post
Share on other sites

Good for you :) Pictures please...

They always help keep me motivated.

Charles

Share this post


Link to post
Share on other sites

Did not take a single pic. I was too determined, to greasy and too worried to even think about it, but next time I jack it up I will take a pic of the front differential mount set up. That's about the only thing that is different than stock.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.