LSD? To Have Or Not To Have

[Tom Berry]

Mako,
I have a complete rear diff assy for a 99 10ae that is all original with LSD that I would make you a good deal on sir. 39k miles on it.
OOORRRRR I have a 06 Solstice N/A with a 5 speed that I will sell you. ALso pretty darn reasonable ! Only $ 7,500 clams.
Tom

[Sebastian Rios]

Dude, ditch the Miata and get the Solstice $7500??? WOW!

That high mileage S2K looks like a pretty good deal too.

[Leonard Cachola]

Wish I had $7500 ... and a garage!

[Rob Schneider]

You've got quite a bit of body roll. Is it possible that you're at full extension of the rear suspension?



Bob

[Mako Koiwai]

That would be correct.

New A arm going in today, and then I can go over to Henry's to check the reservoirs. If the fronts were flat, they weren't doing their part ... and might have contributed to the sway bar bits breaking.

[James Wilson]

Mako,
I have a complete rear diff assy for a 99 10ae that is all original with LSD that I would make you a good deal on sir. 39k miles on it.
OOORRRRR I have a 06 Solstice N/A with a 5 speed that I will sell you. ALso pretty darn reasonable ! Only $ 7,500 clams.
Tom

DAMMIT!!!!!!!

[Jayson Woodruff]

I'm courious, what did you do to 'bring to legal stock height'. Height itself is not a 'requirement', but I'm assuming you mean you put stock legal springs back in.

Jay W

[Mako Koiwai]

springs were always stock ... just raised the spring perches.

[Steve Ekstrand]

I'm courious, what did you do to 'bring to legal stock height'. Height itself is not a 'requirement', but I'm assuming you mean you put stock legal springs back in.

Jay W

Perch height is a requirement.
Stock spring is a requirement.

Where the car ends up is where the car ends up.

[Rob Schneider]

That would be correct.

New A arm going in today, and then I can go over to Henry's to check the reservoirs. If the fronts were flat, they weren't doing their part ... and might have contributed to the sway bar bits breaking.

What I was trying to get at was that, if I understand the situation, the broken front bar mount occured this last weekend, and the problem with the rear wheel existed prior to that time. The problem also got worse when you raised the rear ride height. I don't know what the travel is on your Penske rear shocks, but it is possible that raising the rear ride height reduced the available extension on the shock - to the point where it lifts the rear wheel off the ground.

Bob

[Marshall Grice]

I'm courious, what did you do to 'bring to legal stock height'. Height itself is not a 'requirement', but I'm assuming you mean you put stock legal springs back in.

Jay W

Perch height is a requirement.
Stock spring is a requirement.

Where the car ends up is where the car ends up.

but extended shock length has a +/- 1" allowance. I would suspect that the amount of preload on the front shock/springs would be very important to rear wheel lifting behavior.

I would make sure that the lower spring perch is set the correct distance from the lower shock mount and then make sure that the fully extended length of the front shocks is 1" less then the factory shock.

along the same lines i would make sure the rear shocks are at the top end of the allowance for extended length.

[Mako Koiwai]

Looks like we found out why the sway bar attachment point on the A arm AND the endlink all broke in one loud SNAP.

I was putting in the new A arm ... had all of the suspension bolts loose. I'm jacking up the suspension to ride heights before tightening the bolts ... when I realize that the shock isn't collapsing ... and the entire car is lifting off of the jack stand. Try the other side, and the shock collapses as one would expect. Release the pressure from the right hand side shock reservoir and still, the entire front side lifts off the jackstand.

Looks like we have a seized shock. Pulling it now to take over to Guy ....

[Leonard Cachola]

Looks like we have a seized shock. Pulling it now to take over to Guy ....

Probably explains the rear wheel lift as well...

[John Coffey]

Looks like we have a seized shock. Pulling it now to take over to Guy

Wait! If you replaced suspension bushings/monoballs around the same time you replaced the shocks, check them first. There's a lot of anti-dive in the back of the Miata suspension and those could be causing your bind.

[Jeff Wong]

Looks like we have a seized shock. Pulling it now to take over to Guy

Wait! If you replaced suspension bushings/monoballs around the same time you replaced the shocks, check them first. There's a lot of anti-dive in the back of the Miata suspension and those could be causing your bind.

Bingo, the shocks are fine, probably something small that was overlooked.

[Mako Koiwai]

After putting on the new A arm, I was jacking up the front suspension to ride heights before tightening the bolts ... when I noticed the car was lifting off of the jack stand. Tried it a few times, made sure ALL of the right front suspension bolts were loose. Sway bar was not yet connected ... waiting for the proper ride heights.

Had Karen come out to witness that indeed, the car was lifting off of the jack stand when I tried to jack up the suspension ... small jack under the outer end of the A Arm. Rebound was set to four turns off of full stiff for street driving. Compression at 3 out of 6. Tried different settings. No change ... A arm would not lift without lifting the entire corner of the car.

Tried the same thing on the left front suspension and the shock/spring compressed as you would expect. No issues there.

Tried the other side again. Checked to make sure there was pressure in the reservoir. There was ... emptied the reservoir. Tried it again, car comes off the jack stand ... no compression of the shock/spring.

Call ProParts, Guys at lunch, talk to Jeff, leave Guy a message. Discuss bringing the car to ProParts, but Jeff says probably better not to with the "seized" shock and now no pressure in the reservoir. One would think this happened at the last practice when the sway bar endlink and A arm attachment point snapped ... after which we each did our three lousy laps and drove home.

Pulled the Shock, tried to compress it ... spring is still on it ... won't budge at all, as one would suspect with the spring in place. Deliver it to Guy.

Come home and find an email from Guy that it's functioning properly ?!

No one is blaming anyone for anything ... just trying to get the car working for the next event ... and clear up our traction problems ?!

[Mako Koiwai]

What could have been overlooked? I'm willing to try anything ...

[Jeff Wong]

What could have been overlooked? I'm willing to try anything ...

Honestly the most common problem is the bushings at the top hat. If you tighten them down to the point where it wont let the shock move in an arc, that could cause binding issues.

[Mako Koiwai]

And after I took off the shock ... the suspension was all floppy.

[John Coffey]

And after I took off the shock ... the suspension was all floppy.

You need to check the upper and lower shock mounts to make sure they articulate properly. If you're running monoballs make sure the ball is not bottoming on a bolt or clevis at full angularity. If you're running Delrin or Aluminum bushings, make sure the the bushing only moves in one plane, Delrin and AL bushings cannot articulate.

Also check to make sure the shock or spring is not contacting anything. Sometimes the eyelet at the top or bottom of the shock hits the clevis if there's not enough clearance in the design. A blade upper mount (threaded shaft) can sometimes hit the side of the mounting hole. Upper spring perches sometimes bottom against sheetmetal or a control arm.

[Mako Koiwai]

stock class, stock bushings. Pretty simple straight forward Miata design. Nothing hitting anything, just like the OK left side. I made sure the balls had good movement to them when I installed the rebuilt Penske's earlier this year.

Going over to pick up the checked out shock from Guy. He said that the top nut was too tight ... but I was just following the sample oem Bilstein assembles, ie. left the same amount of threads sticking out above the top nut. Perhaps the Penske rubber bushing was stiffer and didn't need to be tightened down as much? I'm sure the OK left side shock top nut is just as tight, and that side is not having any issues. I'll match it to whatever Guy sets the right hand one to.

[Bob Beamesderfer]

stock class, stock bushings. Pretty simple straight forward Miata design. Nothing hitting anything, just like the OK left side. I made sure the balls had good movement to them when I installed the rebuilt Penske's earlier this year.

Going over to pick up the checked out shock from Guy. He said that the top nut was too tight ... but I was just following the sample oem Bilstein assembles, ie. left the same amount of threads sticking out above the top nut. Perhaps the Penske rubber bushing was stiffer and didn't need to be tightened down as much? I'm sure the OK left side shock top nut is just as tight, and that side is not having any issues. I'll match it to whatever Guy sets the right hand one to.

Same amount of threads? What about the torque spec?

[Mako Koiwai]

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?

[Bob Beamesderfer]

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?

Why don't you ask the mechanic who installed it? Or pull one of the stub axles.

[Mike Simanyi]

Mako,

Disconnect the front bar entirely while the car is on jackstands and confirm it's moving freely in its bushings.

Mike