Step By Step Pictoral Guide to OBX Washer Replacement

[rbryant]

As we all know the belleville washers in the OBX diff seem to be cheap and prone to cracking. They won't stop the diff from working if they crack but they will stop it from working when one tire is completely spinning freely. this happens when one tire is off the ground or has extreemly poor traction like on ice. It also means that one tire CAN spin without the other catching in some cases.

These differentials are a torque biasing differential. If one tire has zero traction the other wont spin because zero times the torque bias is still zero. Granted this shouldn't be a common occurance but the washers are there to give you a phantom grip type effect in those cases and still allow some torque to be transferred to the non slipping wheel.

Here is a step by step process for replacing OBX belleville washers:

Here is a picture of the inside of the OBX with the upper worm gear, inner gears, and washers dissassembled:

http://rbryant.freeshell.org/obx_assembly/OBX%20assembly%20003%20(Small).jpg

Step 1: Place the thinner of the two gears inside the center retainer.

http://rbryant.freeshell.org/obx_assembly/OBX%20assembly%20004%20(Small).jpg

Step 2: Place the stacked washers inside of the gear. They should be stacked like this )()()(
http://rbryant.freeshell.org/obx_assembly/OBX%20assembly%20005%20(Small).jpg

http://rbryant.freeshell.org/obx_assembly/OBX%20assembly%20006%20(Small).jpg

Step 3: Place the thick gear over the washers (it will stick up past the top of the inner retainer if assembled properly to provide preload)
http://rbryant.freeshell.org/obx_assembly/OBX%20assembly%20007%20(Small).jpg


If you are talented you can put them all in at once. They will fit inside of the gears like this (notice the preload is there because the two gears are held apart by the belleville springs):

http://rbryant.freeshell.org/obx_assembly/OBX%20assembly%20001%20(Small).jpg


Step 4: Put the center worm gear back in.
http://rbryant.freeshell.org/obx_assembly/OBX%20assembly%20008%20(Small).jpg

Step 5: Put the top back on the diff

Note the dowl pin...
http://rbryant.freeshell.org/obx_assembly/OBX%20assembly%20009%20(Small).jpg

It aligns with this notch..
http://rbryant.freeshell.org/obx_assembly/OBX%20assembly%20010%20(Small).jpg

From the top it goes in the back side of the hole that is not like the others (around 5 o'clock in this picture)

http://rbryant.freeshell.org/obx_assembly/OBX%20assembly%20012%20(Small).jpg

Step 6: Put the bolts in and torque them down to 30 ft*lbs
(out of pictures for the thread...) I suggest putting the diff in a vice. The passenger side has a flat spot in it that can be used to hold it in place.

BTW: If you tear it down and wonder how it works I think this article By Dave Coleman of Sport Compact Car does the best job that I have seen of describing it: http://www.sportcompactcarweb.com/projectcars/0205scc_project_ford_focus_zx3_part_4/


Let me know if you have questions or comments.

If you want/need a set of washers just send me a PM and I can hook you up!


-Rich

[DOG-DID-IT]

Nice Write-Up! :thumb:

Step 6: Would it be a good idea to put Loctite on the bolts?

Thanks!

[BIG PSI]

Thanks Rich on that write up.... I wonder if I am going to have problems with mine as well. I had the transmission built in CANADA, with the OBX installed in at that time. I have yet to install it in a vehicle. Do I need to take it out and check it ???

Chuck

[Speedeuphoria]

Do I need to take it out and check it ???Chuck

hard to say. it depends on how much of a perfectionest you are. I would just to make sure the bolts are torqued properly and the gears are deburred and washers are intact, ect.. But thats me. It is easier to do it now rather than later

[rbryant]

I didn't use any loctite on mine. If you were to use some I would say that blue is probably better than red for these since who knows how strong they really are and you might snap one if you ever took it apart again.

I didn't really mess with the gear ends either.From what I understand about how they work it wouldn't really matter if they are rough on the end because they don't spin when they are stuffed against the end of the pocket. They have a force against the pocket which would would stop them from spinning.

I am not sure I would take it apart if it is already in the tranny or not. If the diff has already been shimmed it shouldn't be too bad of a job to take it out and put it back in. The initial install is what is tough because the preload must be checked. If it was shimmed properly taking it out and putting it back in shouldn't change the preload.

-Rich

[looneytuner]

Just saved this to my hard drive. Thanks!!!!!!!!!!!!!!!!!!!!!!

[rbryant]

All,

I got the washers in and they are a perfect match here are comparison pictures:

http://rbryant.freeshell.org/obx_assembly/OBX%20washer%20comparison.jpg

The darker one on the upper left is an original. The bottom shows them stacked on top of each other to show that the holes match.

Just send $15 to rich_bryant_is(at)yahoo.com via paypal and I will ship them out.

-Rich

[2.216VTurbo]

Are the new washers you found obviously of better quaility?

Do you get more height (preload) out of them?

Everything is all bolted in and my TC is 6-8 wrenching hours away from running again after ten months, should I just bite the bullet, order a set and pull the diff back out?:o

[rbryant]

They won't give more preload. The height won't give more preload anyway because they have a fairly constant spring rate. compressing it a little less or a little more won't change the amount of force it only changes how far you can compress it.

I can get thicker washers if you would like (making a bigger spring with more force). I put thicker ones in my OBX but don't have the car running yet. I am not sure if it will be better. It might be harder to turn with thicker washers.

With that said if everything is back together it probably isn't worth tearing it down. If they break it will still work but might loosen up a bit.

-Rich

[rbryant]

Can one of the admins change the torque spec I said down to 30 ft*lbs? This might be on the tight side of things... I am past the editing window so I can't change it... :(

Thanks,

Rich

[rbryant]

Check out this thread showing an authentic honda quaife teardown. Like the OBX it has only 5 helical gears on each side:

http://www.highaltitudeimports.com/showthread.php?p=417720#post417720

-Rich

[TurboGLH]

Just a couple more suggestions.

We also retap all the bolt holes, the machine work on these is just a little on the rough side and there seems to be enough of a variance that it's worth while.

I also run a die down the bolts as the crappy job tapping the holes from the factory messes up the threads on some, this way we don't have any interference affecting the readings from the torque wrench.

On the topic of torque, we also only tighten ours to 200in/lbs. That's pretty much standard for a 8mm x 1.25mm fastener, and while the bolts seem to be of an ok quality it didn't seem prudent to exceed that number by such a large factor unless obx said so. I know that 30ft/lbs is the number used by quaife, but their whole assembly is worlds away from the obx in terms of quality.


Check out this thread showing an authentic honda quaife teardown. Like the OBX it has only 5 helical gears on each side:

http://www.highaltitudeimports.com/showthread.php?p=417720#post417720

-Rich

Strange, I'm 95% positive that the neon and 568 ones use 6 gears vs the 5 used in the obx. Must be a packing issue, not able to fit 6 in the diameter available.

[rbryant]

Just a couple more suggestions.

We also retap all the bolt holes, the machine work on these is just a little on the rough side and there seems to be enough of a variance that it's worth while.

I also run a die down the bolts as the crappy job tapping the holes from the factory messes up the threads on some, this way we don't have any interference affecting the readings from the torque wrench.

On the topic of torque, we also only tighten ours to 200in/lbs. That's pretty much standard for a 8mm x 1.25mm fastener, and while the bolts seem to be of an ok quality it didn't seem prudent to exceed that number by such a large factor unless obx said so. I know that 30ft/lbs is the number used by quaife, but their whole assembly is worlds away from the obx in terms of quality.

Thanks for the input. Mine is already set at 30 ft/lbs but you are right, there are a lot of those bolts and it isn't worth over stressing them when there is no need to.

-Rich