LSD? To Have Or Not To Have

[Mako Koiwai]

It was moving fairly freely. Guy said it should move easily with two fingers, so last night i added another layer of thin washers under the "straps" to relieve pressure. Up to three washers. It slowly falls on it's own now.

Also added split rings to keep it from wandering, but it was (still) almost perfectly centered. I had wanted to add collars in the past but there wasn't room for them because of the HD mounts. Last night I added some syntheitc spacer rings (made by Whiteline as differential bushings) so that the actual collars could be a bit more in-board and thus clear the HD mounts. Everything is greased. Photo to follow.

[Mako Koiwai]

Bob ... Karen seems reluctant to ask the mechanic who did the job? He's someone in the AX'ing community in SD.

Going to read up on axle pulling in my shop manual.

From the on-line reviews, the nearest Mazda dealer/garage is in Glendale. I've NEVER seen a business have such universally horrible reviews!!!

But there is an independent Mazda garage in Alhambra, fairly close by that gets very good reviews, so I might just have them do it.

[Mike Simanyi]

Okay, you're good on the front bar motion. I haven't read the entire thread this morning, but in case it isn't mentioned you should consider removing the shock assembly and make sure motion on the control arms is appropriate.

I have delrin on mine and they move with a little bit of pressure by hand. I'd expect the stock rubber ones to be more difficult to move, but maybe try tapping with a dead blow hammer to see if they have consistent response.

Also John Coffey's comments are good. Make sure you don't have any odd physical interference with any bolts.

If you disconnect the swaybar on the side that's frozen, does it still lift off the jackstand under pressure? Maybe there's some bind in your endlinks.

Mike

[Jason Isley BS RX8]

I had the rear of the Miata up ... when I turn one wheel the other wheel turns the other direction ... but just a bit ... not at the same speed as the wheel I'm turning. Tranny in neutral.

With the opposite wheel held lightly in place, I can freely turn the wheel in front of me.

Does this give us any clues as to whether the Miata Torsen LSD is installed? Reminder ... a couple of years ago the LSD in Karen's Miata "broke." Made a lot of noise. She left the car with a AX mechanic down there who happen to have another used dif that he could install. I'm not 100% confident that he actually put in the LSD dif?

Read the link I posted on how to check for an LSD. :ibrightdea:

[Bob Beamesderfer]

Bob ... Karen seems reluctant to ask the mechanic who did the job? He's someone in the AX'ing community in SD.

Going to read up on axle pulling in my shop manual.

Is it Larry D.? Why not ask him? He did the work, he should know what parts he used and be willing to say.

[Mako Koiwai]

[Mako Koiwai]

Mike ... sway disconnected ... the endlink AND attachment point on the A arm actually got ripped apart.

With the shock off, suspension bolts all lose, everything moves very freely. Put the shock back on, after Guy dyno checked it and said it was perfect, and the car still lifts off of the jack stand, but that shock is now compressing somewhat. I'll do some little video clips.

Jason ... I did read your LSD link ... but there are other opinions out there that are the opposite ?!

[Mako Koiwai]

BTW. Guy got laid off at ProParts yesterday.

If you need any between season shock rebuilds or other car work, please keep him in mind. I've got his phone number.

[Mako Koiwai]

Talked to Larry ... he feels it might not have been a LSD dif that he put in. He claims that one CAN see enough thru the fill hole and that's the easiest way to double check. He also said that he THINKS that all automatics and LSD cars had a fairly large counter weight where the drive shaft attaches to the dif?

[Bob Beamesderfer]

Talked to Larry ... he feels it might not have been a LSD dif that he put in. He claims that one CAN see enough thru the fill hole and that's the easiest way to double check. He also said that he THINKS that all automatics and LSD cars had a fairly large counter weight where the drive shaft attaches to the dif?

The automatics maybe, which BTW, all came with open diffs. Isley linked to an article written by the expert on the subject.

Is Karen a Team Support Member? You could call Motorsports Development and ask their opinion.

[Jason Isley BS RX8]

Torsen on the left, but having this damper does not mean 100% you have the diff.

[Mako Koiwai]

Yes, MazdaSport is our friend

[Mike Simanyi]

With the shock off, suspension bolts all lose, everything moves very freely. Put the shock back on, after Guy dyno checked it and said it was perfect, and the car still lifts off of the jack stand, but that shock is now compressing somewhat.

WIth the shock and spring out and the control arm bolts torqued to spec, try rapping both control arms with a deadblow hammer or a regular hammer, applying pressure to a 2x4 held against the arm. Do they both move the same? Try the same on the other side that is working properly and see if that responds the same as well.

The bushings could be improperly installed causing a bind condition or perhaps the mounts on the "bad" side have been tweaked and only cause a bind when fully torqued.

Mike

[Mako Koiwai]

OK Mike

... new bushings installed a couple of months ago ... professionally.

I've got the car sitting on Jack Stands under the end of the A arms ... so that I could torque down all of the suspension bolts at ride heights ... but the car is sitting quite a bit higher then usual. Bolts loose, sway bar disconnected. In front, distance between center of whee to the inner fender lip is about 15" ... usually it should be around 13.5"

Probably a leverage thing. If I could safely get the jack stand further out on the arm the car would lever down.

I remember now that Guy was saying that they strap down their cars, with the A arms sitting on a rack ... probably in order to get to their desired ride heights.

I think I would do better doing each corner separately, jacking up each A arm to the proper ride heights.

[Bob Beamesderfer]

Hub-to-fender lip measurement isn't precise, but this is way off.

If it's normal on one side and off on the other, something is binding and probably something is bent.

[Mako Koiwai]

no, both sides are equal now.

Are you saying that I should be close to approx. ride heights with the A arms sitting on the jack stands as in the photo?

[Bob Beamesderfer]

no, both sides are equal now.

Are you saying that I should be close to approx. ride heights with the A arms sitting on the jack stands as in the photo?

No, because tires deflect and jack stands don't. Still, the important issue that you mentioned about how one side moved freely and the other didn't might not exhibit with a static ride height measurement. While suspension is compressed by mass under load, decompression is dependent on damping, spring rate and gravity as mass removed from that corner. That makes decompression more effected by a binding suspension.

[Mako Koiwai]

Check out the movement of the top of the Penske shock ... with the top nut loosened as recommended to eliminate possible binding. I think it's excessive ... and would like to screw the top nut back down - so that the big rubber bushing is crushed a bit more. I HAD them with 3/4 inch of thread exposed. The loosened position has 1/2 inch of thread exposed.

http://blip.tv/file/1494242/

[Mako Koiwai]

The mechanic that changed out the differential when it blew in SD a couple of years ago doesn't know if it was a LSD or not because he didn't replace the innards; he replace the entire dif housing with guts. MazdaSport says that just because that counter weight is on the drive shaft doesn't prove anything. Bryan at MazdaSpeed says the only thing you can do is open up the housing. And call back on Monday to talk to Tim.

He thought that if you turn both the drive shaft AND one wheel, the other wheel should turn in the same direction if you have a Torsen LSD.

The mechanic said that if you look thru the fill hole you will see either Worm gears = Torsen LSD or Spider Gears = open dif. I could see neither ... which is what MazdaSport also said.

You can see from the photo that the fill hole is offset. All one could see is brownish rough metal.

[Steve Collins]

I love the star filter effect you got on the differential oil. How long did it take you to light this shot?

[Tom Berry]

So.. Mako. If you need a torson rear diff. I have one here at the house.
Tom

[Mako Koiwai]

The entire assembly or "just" the LSD itself?

We STILL don't know what we have in there. The mechanic who put it in a couple of years ago now thinks it was not a LSD. Monday I'm suppose to talk to Tim at MazdaSports.

[Tom Berry]

Mako.
Its the whole rear diff assy. Looks like it has never been apart. The car had 39k miles on it.
Tom

[Bob Beamesderfer]

Check out the movement of the top of the Penske shock ... with the top nut loosened as recommended to eliminate possible binding. I think it's excessive ... and would like to screw the top nut back down - so that the big rubber bushing is crushed a bit more. I HAD them with 3/4 inch of thread exposed. The loosened position has 1/2 inch of thread exposed.

http://blip.tv/file/1494242/

That doesn't look good. So, why are you measuring exposed threads instead of torquing it to spec?

[Mako Koiwai]

Because I can't find torque specs for the Penske's ... and I want to keep an eye on the shaft while I tighten it down ... to make sure it doesn't spin. Using the usual torque wrench, I would need a fairly deep socket, which would cover up the shaft. On the other hand, the shaft doesn't seem to be showing any inclination to turning ... while it's mounted to the car.

The Penske that ProParts assembled showed 1/2 inch of threads. The one I did showed 3/4 inch threads. That shock isn't binding ... so for the time being I tightened the "loose" one 1/8th inch and loosened mine 1/8th inch, so they match. Not as much movement on the one in the video now.