How much SLOP at your rear Wheels?
08-12-2003, 10:36 PM
#1
Melting Slicks
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How much SLOP at your rear Wheels?
I've spoken to a few very helpful folks on this forum regarding my rebuilt differential and trailing arms. I rebuilt it myself, a point of pride if not practicality. $225 for 20 ton floor press, $100 in bearing pullers, $100 for tools to press bearings on, $150 in various micrometers, $350 in parts, plus untold forgotten misc. stuff costing $$. Yes, I saved a fortune doing it myself! I also tell myself it is still cheaper than golf.
Anyway, my differential and trailing arms appear to check out perfectly to specs. I checked each clutch pack, one side at a time, and set to less than a couple thousandths clearance measuring from each of the small pinion gears while the clutch pack was preloaded with an appropriately sized screw driver between the side gear and the pivot shaft. Once everything was set up, side yokes installed and c clips attached, I had less than .002" clearance at rest between the end of the side yoke and the pivot shaft.
However, when I jack up the rear and grab the wheel at the 12 and 6 o'clock positions, I can really shake it. It feels very loose. When measured, the play at the yokes is only about .010". The hub in the trailing arm is less than .002" movement. But at the tread it feels like it must be an inch! In truth, it is only about 3/16th's of an inch at the tread, but it sure seems to be a sloppy arrangement. If I raise the wheel with the floor jack so the half shaft is parallel to the ground and without the trailing arm being bolted to the rear leaf spring, this side to side action by pushing and pulling on the tire at the 12 o'clock position is 1/8th of an inch at the tread. Better, but still sloppy.
My problem is, I don't recall shaking the wheels this way when the cars were new. i.e. my 79 L82 nor the 69 when I bought it in 1973. Is this just a POS design like all the Porsche guys said it was? or should I still keep looking for something else? GKULL was kind enough to excuse himself from the phone for a few minutes to go out to his garage, jack up the car and check his! What a guy :smash: Anyway, his special rear end had NO slop whatsoever.
Norval's 6 link is looking better all the time!
I just want to get the car back on the road! I was ready to just call it a day saying good enough for government work and go to the next phase of my project, but decided to inquire here first. I will always regret not doing it right if I have missed something!
Frustrated,
Chuck
Anyway, my differential and trailing arms appear to check out perfectly to specs. I checked each clutch pack, one side at a time, and set to less than a couple thousandths clearance measuring from each of the small pinion gears while the clutch pack was preloaded with an appropriately sized screw driver between the side gear and the pivot shaft. Once everything was set up, side yokes installed and c clips attached, I had less than .002" clearance at rest between the end of the side yoke and the pivot shaft.
However, when I jack up the rear and grab the wheel at the 12 and 6 o'clock positions, I can really shake it. It feels very loose. When measured, the play at the yokes is only about .010". The hub in the trailing arm is less than .002" movement. But at the tread it feels like it must be an inch! In truth, it is only about 3/16th's of an inch at the tread, but it sure seems to be a sloppy arrangement. If I raise the wheel with the floor jack so the half shaft is parallel to the ground and without the trailing arm being bolted to the rear leaf spring, this side to side action by pushing and pulling on the tire at the 12 o'clock position is 1/8th of an inch at the tread. Better, but still sloppy.
My problem is, I don't recall shaking the wheels this way when the cars were new. i.e. my 79 L82 nor the 69 when I bought it in 1973. Is this just a POS design like all the Porsche guys said it was? or should I still keep looking for something else? GKULL was kind enough to excuse himself from the phone for a few minutes to go out to his garage, jack up the car and check his! What a guy :smash: Anyway, his special rear end had NO slop whatsoever.
Norval's 6 link is looking better all the time!
I just want to get the car back on the road! I was ready to just call it a day saying good enough for government work and go to the next phase of my project, but decided to inquire here first. I will always regret not doing it right if I have missed something!
Frustrated,
Chuck
08-12-2003, 11:54 PM
#2
Race Director
Re: How much SLOP at your rear Wheels? (Chuck Harmon)
I'll give your thread a little nudge.
Did you remember to torque the lug nuts tp spec? :)
Something does not add up. Seriously, it sounds like the only possible place the variance could be is where the tire mounts to the wheel. How bad was the slop before you got started?
I will check mine the next time my car is in the air. Hopefully Van Steel can chime in with some ideas. These guys know our rear suspension quite well!
Also, did you speak w/ Guldstrand?
-Steve
Did you remember to torque the lug nuts tp spec? :)
Something does not add up. Seriously, it sounds like the only possible place the variance could be is where the tire mounts to the wheel. How bad was the slop before you got started?
I will check mine the next time my car is in the air. Hopefully Van Steel can chime in with some ideas. These guys know our rear suspension quite well!
Also, did you speak w/ Guldstrand?
-Steve
08-13-2003, 01:04 AM
#4
Race Director
Re: How much SLOP at your rear Wheels? (Stoge)
Chuck's strut setup is fairly new.
I forgot to ask, does the rotor have as much play as the tire? Is the play the same if you pull on the slots in the rim as when you pull on the tire?
-Steve
I forgot to ask, does the rotor have as much play as the tire? Is the play the same if you pull on the slots in the rim as when you pull on the tire?
-Steve
08-13-2003, 02:23 AM
#5
Melting Slicks
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Re: How much SLOP at your rear Wheels? (Stoge)
Stoge,
Good suggestion, but in my case the lower control arms are new Guldstrand units with heim joints, no slop whatsoever. The U joints are also brand new.
Pacin,
The rotor is clamped firmly to the wheel hub by the sheel held by the lug nuts, no slop.
Chuck
Good suggestion, but in my case the lower control arms are new Guldstrand units with heim joints, no slop whatsoever. The U joints are also brand new.
Pacin,
The rotor is clamped firmly to the wheel hub by the sheel held by the lug nuts, no slop.
Chuck
08-13-2003, 08:13 AM
#6
Re: How much SLOP at your rear Wheels? (Chuck Harmon)
Chuck i've had the same problem and have taken them apart twice but its still happening. I don't have the solution but will be watching with great intrest for replys. John :cheers:
08-13-2003, 08:37 AM
#7
Team Owner
Re: How much SLOP at your rear Wheels? (johns73)
Chuck, I think you are being a bit worrysome, not to worry too much though, these sharks are massing for an attack..... :D :D :eek: :eek:
I jacked mine up just now....top of my tire moved in and out maybe as much as 1/4 inch, but I gotta really tug pretty good to get it to do that....hard to say how much of that is tire flexing, vs wheel movement...can't visualize it too well, tried a sway bar on a pivot under the wheel, and got NO movement at all.....at 3-9 oclock I got NO movement....my tire wear is totally normal....
GENE
I jacked mine up just now....top of my tire moved in and out maybe as much as 1/4 inch, but I gotta really tug pretty good to get it to do that....hard to say how much of that is tire flexing, vs wheel movement...can't visualize it too well, tried a sway bar on a pivot under the wheel, and got NO movement at all.....at 3-9 oclock I got NO movement....my tire wear is totally normal....
GENE
08-13-2003, 08:50 AM
#8
Premium Supporting Vendor
Re: How much SLOP at your rear Wheels? (Chuck Harmon)
When we rebuild out t-arm assemblies we build them to 0 - 1/2 thou run out. You have just a little more but i don't believe it will cause that much movement. What did you torque your spindle nut to. It should be 100 lbs. Thats the nut on the backside of the t-arm where the flange for the 1/2 shaft flange gets bolted to. That flange also has a washer on it.
08-13-2003, 12:05 PM
#9
Melting Slicks
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Re: How much SLOP at your rear Wheels? (Chuck Harmon)
Thanks very much for the replies!
I just got off the phone with Dick Guldstrand, no joke. He said my movement is very normal and not to worry about it. He said that the clutch pack does compress under such twisting forces created by the 12/6 o'clock push and pull which will cause the movement I get out at the tread.
He stated that the lower control arm really does most of the work when cornering, that the half shafts and side yokes are really more of a locating device. He went on to say that a number of guys even leave out the "c" clips on the yokes to allow for quicker rear gear changes, though that is not something he would do or encourage.
I feel much better now!
Chuck
I just got off the phone with Dick Guldstrand, no joke. He said my movement is very normal and not to worry about it. He said that the clutch pack does compress under such twisting forces created by the 12/6 o'clock push and pull which will cause the movement I get out at the tread.
He stated that the lower control arm really does most of the work when cornering, that the half shafts and side yokes are really more of a locating device. He went on to say that a number of guys even leave out the "c" clips on the yokes to allow for quicker rear gear changes, though that is not something he would do or encourage.
I feel much better now!
Chuck
08-13-2003, 12:33 PM
#10
Race Director
Re: How much SLOP at your rear Wheels? (Chuck Harmon)
I feel much better now!
Chuck
Chuck
Seriously though, glad to hear everything is under control.
-Steve