I finally dropped the rear cage for working on a brake caliper leak ('90 Coupe, Salisbury diff). During disassembly I noticed a few drops of diff oil on the pinion shaft so I removed the 1 1/16 nut, took note of the shaft position and pulled it out.
First question: After seal replacement, is there a particular procedure on how to torque the pinion nut? I am reading on this forum about a “crush sleeve” which confuses me.
On the output side - after removing the brake discs - I consider replacing the output shaft seals as well. I have not yet removed the output shaft/stud assembly which I believe I have to in order to get to the output seal.
Second question: Looks like there are 4 bolts holding the shaft in place. Do I just need to loosen these bolts and pull the shaft out to have access to the seal? Any puller or special procedure required?
Complicated question, on the pinion, at minimum you have to return the nut to the same position after seal replacement. This is to ensure the same preload on the bearings. If you didn’t mark the nut and pinion, the only correct way to do it is to replace the crush sleeve and measure the rotational torque to turn the pinion; spec is for new bearings and means complete differential disassembly.
The output flange seal can only be accessed by removing the assembly (5 bolts on the Salisbury); a few light taps will free it. Then release the tab washer and big nut to withdraw the flange/shaft which allows access to the seal. There is a collapsible spacer in there also, and the correct way to set preload is with a new spacer (and new bearings) as rotational torque is used to set the preload.
You can also get the output assemblies exchange/rebuilt; in the US Coventry West comes to mind.
Coventry West recently did one of my output housing/bearing/shaft assemblies where a bearing failed. About $200 plus shipping including parts and labor. Took about a week.
There is a video on YouTube about the DIY process. After watching it, I decided to let them do it, because setting the preload is not a simple operation, and tools I don’t have. Output rebuild
thanks! I have the original position for the nut on pinion, so I will try that first.
Re the output flange seal: If I understand you correctly then you are suggesting to remove the assembly via the 5 bolts and then send this assembly to Coventry West for rebuilt/exchange, not the entire diff. . Correct? I am tempted to do so as I do not have the required tools to manage myself.
jal5678: Thanks for the video link. Convinced me not to try myself
Yes, just the output shaft assemblies. I have done the output assemblies, it takes some serious grunt to set the preload. I did not have the 2 1/4” wrench; I clamped the nut in the vise and turned the flange with a bar and 3’ pipe and still struggled. Plus it is easy to mess up the new seal because everything wobbles around while tightening. For a job that is such a pain to even access, probably better to have an expert do it if you can afford it.
As far as the pinion nut is concerned l think returning to the marked position is not the end of the install.
The recommended pinion turning torque for used bearings should be researched and if original nut position gives you LESS than that figure the nut should be carefully tightened more until the required torque is reached.
The reading must be taken only through the backlash movement of the pinion.
The manual gives the procedure, you measure the rotating torque prior to disassembly- there is no published torque for used pinion bearings (as other manufacturers provide). He already had removed the pinion nut…
Output shaft seals:
It would be a very good idea to change the bearings as well.
I did it my self, it’s not the easiest job but doable, the hardest part is determining the preload.
You will need new crash sleeves as well.
Pinion seal is very easy, tighten the nut to the exact same position as it was.
Great info - Thanks! I appreciate the link to the relevant thread…
I will tighten the pinion nut to the former, original position and will measure rotation torque as per thread info. Hopefully this will be sufficient. I missed to measure torque prior to disassembly - my fault. Well, I guess this falls into the “learning by doing” department.
Just out of curiosity: What are symptoms for having lower resp. higher torque at the pinion nut during assembly when driving the car?
Got in touch with Coventry West and will mail the output shaft assemblies today (7-10 days turnaround)
Hi Stephan-
Set the pinion nut back to the previous position and drive the car. If it is quiet, with no or at least acceptable gear whine, leave it be. You can mess with the torque if it is noisy, and messing with it might make it better or worse.
Regards-
Bob
That could also be bad u-joints in the drive shaft. Grab and rotate the drive shaft with the tranny in park and the handbrake on. You can then see where any play/lost motion is between the tranny and the output flanges of the diff.
The knock be a few different things. Transmission mount, something loose around the rear cage or exhaust, a shock bushing, something in the trans itself. Before you start changing preloads on the differential pinion, make sure you have confirmed 100% that is the source. It’s easy to make things worse, and once you do that, you’re usually in for a rebuild.
Just checked the drive shaft: zero play! It is only one knock when I engage reverse. Transmission mount was just done, shocks are new. So I will put the pinion nut back in its original position and measure the rotational torque to see where I am at.
Could also be the U-joints at the half-shafts, play at the hub spline, broken hub, or play at any of the suspension bearings.
Since the cage is out you should check/change all of the above, plus new brake discs - pads - handbrake.