Bairs rebuilt rear spindles seem too stiff ???

[Warren L.]

spindles

Well that is alot of posts for a guy who measured his bearings wrong in the first place.

Push a tappered roller bearing to one side and rotate it 7-10 times under load, then pull it back there is your end play.

The two Timken engineers who explained this to me could be wrong but my dial indicator showed them to be correct. When you do this they will seat. My reading changed as the bearings were rotated under load and pushed to one side

If GM said use a pry bar then a moron wrote that statement. I checked this with a guy who races and we did it together and it was correct just as the engineers said.

I showed them the spindle set up tool and asked it was okay, they said no, bearings have a tolerance, and your spindles have a tolerance. Interferance fit bearings can expand depending on tolerances. We set them up for .0005 end play before grease. The seals caused drag and probably the grease as well, I think there was seperate grease for the seals that is to be used so they don' wear into the spindle.

There is lots to check in a spindle, anyone ever check their crush collars?? My orginal GM crush collar at least one of them was only partly machined, it was not parrallel so it got replaced. Check both the bearing seats in the housing to be sure they are parrellel, think GM makes everything right or maybe there was never any damage to the trailing arm??? Want to be sure there is a bunch of stuff to look at.

I have a ton of info recorded but can't open the file for some reason and am too busy with work right now but was very happy with the Timken bearing engineers. Also talks with Van Steel he knows the stuff inside and out, sure Bears is fine and you are feeling the drag from seals and grease.

Do you think that measuring a bearing and a change with grease is relevant, I think measure it under load with the weight and forces acting on it would make sense.

Warren

[Clem Z.]

tom,is ralph johnson still at crane??? *NM*

[Joe R.]

Re: Bairs rebuilt rear spindles seem too stiff ???

Hi Joe L:

For the cases where you set up your spindles dry for 2 mils and then measured 0 mils after they were greased and reassembled, did you use the exact same spindle, collar, and shims for both measurements?

I have never seen one of those special tools that the professionals use for determining the desired shim thickness, but if that tool does not have the same degree of interference fit that the spindle has (and I suspect it does not), I can understand why the end play might be less in the final assembly than it was when measured with the tool. As noted by both Tom Dooley and Warren Lake, the interference fit may cause the inner bearing race to expand slightly, which will directly reduce the end play by some small amount.

However, this explanation for the measured difference would not hold up if the exact same spindle, collar, and shims were used for both the dry measurement and the greased measurement. In that case it would seem that the only variable is the presence of the grease.

Joe R

[Michael H.]

YES!! YES!! I AGREE!!

Your engineers are absolutely correct!! You asked if the spindle setup tool was ok and they said NO! "interference bearings can expand depending on the tolerance". They're trying to tell you that the numbers that you get from the slip fit setup are not going to be the same as the actual numbers from the finished assembly with pressed bearings. It WILL be different. It WILL be less.

Bearing inner races will expand as they are pressed on and this increases the total height of the bearing by a factor of somewhere around 10 to 1. (do the math if you want. the angle of the side of a spindle bearing race is roughly 12*) If the press fit expands the inner race .0002", the height of the complete bearing increases by roughly .001". That times two (two bearings) is just about exactly the amount that we've lost during assembly if the initial test fit was .002" using slip fit spindle.

I've been using the slip fit method for decades but I always begin with a clearance of about .004"-.005". When assembled with press fit, it always comes out to .001"-.003".

Some of the folks that reject this information should get on their phone tomorrow and have a chat with some local bearing mfg. Just ask him if the stack height of a bearing and race assy changes when it's pressed on to a shaft.

[Joe L.]

Re: Bairs rebuilt rear spindles seem too stiff ???

Joe-----

No, I now use the special tool for setting the bearing clearance. In fact, I use the specific tool that GM recommends (J-24626). NOWHERE does the GM procedure call for the "addition of extra clearance to make up for the fact that clearances will be different when the bearings are press fit on the actual spindle". Plus, the situation would be absolutely no different if a turned down spindle was used for the tool. The turned down spindle, which was recommended earlier by another, is, essentially, the same thing as the bearing set-up tool, except less convenient. You'll also notice that when the recommendation was made to use the "turned down spindle" there was no mention made by the recommender of any need to increase the set-up clearance to compensate for the press fit on the actual spindle. The recommender came up with that later to help justify his position. The bearing inner races do become slightly "thicker" as a result of the interference fit, but by nowhere near .001" each. The increase is negligible. If the bearing set-up is set at .001-.002", the final end play will be greater than 0.000".

Another point: when I originally did the "experimentation" I described, I did not have a bearing set-up tool. I did not have a turned down spindle, either. So, I set up the bearings using the "real world" spindle. In other words, I installed the bearings dry and assembled the spindle, checked the clearance, disassembled, packed the bearings and re-assembled. If the clearance was not right after the first set-up, I diassembled, calculated the shim I thought I'd need, re-assembled dry, and checked again. Tedious? You bet. It took me hours to do one side. However, when I finally got the bearing clearance set dry at .001-.002", I packed the bearings and re-assembled. After packing the bearings and re-assembly, I could discern no end play in the spindles. So, this "takes out of the equation" the RECENT CONTENTION of others that there is a significant difference between using a bearing set-up tool and the final, "real-world" situation with the press fit bearings on the spindle----at that time I did it ENTIRELY with the bearings press fit on the spindle. I'll also remind that the contention that there is a significant difference in end play using the set-up tool (or, a turned down spindle) versus the actual spindle with press fit bearings was not mentioned by anyone earlier in this thread. If that had been an issue, it would have been very relevent for it to have been raised MUCH earlier in this discussion. It wasn't. That's because that contention was "developed later".

I might add that I was so concerned about the lack of end-play with the bearings greased that I disassembled the unit, cleaned the bearings of grease, and re-checked the end-play dry. I got the same end-play as I originally measured dry just as I reported in a previous post.

So, most of what I reported in my previous post was done with the actual spindles and not the set-up tool. I started using the set-up tool much later. With it, I went through the same process except since it was much less tedious to do repetitive assembly/disassembly, the work proceeded much faster.

Another point: several folks have contended that the increase in bearing race thickness is well known to bearing engineers, bearing suppliers, Van Steel, etc. IF that's the case, then do you suppose that it's unknown to Bairs that have been doing this work as long as anyone?

Basically, what I have reported is not opinion. It is EMPIRICAL. In other words, it's what I have observed based upon experimentation. I conducted these expiriments the same way I conducted experiments in my work of nearly 35 years. Folks can take it or leave it; it makes no difference to me whatsoever. Period.

[Warren L.]

Re: YES!! YES!! I AGREE!!

I was told I could measure this and calculate the loss. I thought about it a bit and said no, I didnt trust my tools or myself to measure that accurately.

The mechanic who helped me wrote down the formula and did the calculations anyway and the actual loss on the spindles was more than the calculations if I remember correctly. I found it interesting that the formula just spewed out of him in two seconds after he looked at the spindles. He had never done spindles before but he is a mechanic who should have been a surgeon, he understands all the principles.

I have never heard anyone talk about measuring a bearing correctly so I always figured well they are off with their spindle tool and under what they think but they are measuring their bearings wrong it all balances out. When I brought this up to the guys who sell the tools they just looked at my like I was a sasquash other than Art at Van Steel who smiled.

I built a tool to dissassmble the spindle easily after it is assembled under load, same spindle same bearings, put it together several times, tested it with oil, did the rotation with load to the side. If I remeber correctly put it in the drill press and may have used it to put a tiny bit of pressure but again have to get back to my notes so long ago and memory is not getting better. Made sure surfaces were were parrallel, had to take one shim down a bit but got them both the same.

Those guys at Timken gave me tons of info, I still chuckle when I think of laying that stuff out on their boardroom table, really nice helpful people. I buy Timken bearings when I can over others just cause I was so happy with the service there, head office in Mississauga.

I would have to look back at my notes cause we got the tolerance we wanted in oil can't remember if we remeaasured after that with grease,probably did since my friend is so dillgent, one day will get someone to see if they can fix that file.

Warren

[Joe L.]

Re: spindles

Warren------

Who is the guy "with all that posts that measured his bearings wrong in the first place"? If you are referring to me, please explain to me how anything I posted indicates that I "measured the bearings wrong in the first place". If I did something wrong, I'd like to know about it. If for no other reason, I want to get it right next time.

GM never said to use a pry bar in the end play adjustment procedure in anything that I've seen. I don't use a pry bar. However, I don't see that a pry bar is an issue, at all.

If the engineers said that they set-up interference fit bearings at .0005" end play before grease, that futher supports what I've been saying. I set them up at .001-.002" before grease. So, I (and most others, for that matter) set them up 2 to 4 times LOOSER than this spec. So, if .0005" end play before grease compensates for the supposed increase in bearing thickness due to interference fit, then .001-.002" should be way more than enough to so-compensate. Actually, even if you mistated the clearance, I feel, based upon my observations, that .001-.002" dry with a set-up tool is more than enough to ensure end-play after installation of interference-fit bearings.

I'm not sure if this is one of the things you're saying but the need to "seat" the bearings by rotating them prior to end-play checking is DEFINITELY CRITICAL. It's one of the "tricks" one has to master prior to being competent at this process and it might be the trickiest part of the whole procedure. I was instructed in this by a friend that's been doing this professionally for over 30 years and has probably rebuilt thousands of trailing arms. I spent quite a few hours just learning how to do this correctly.

[Michael H.]

Thanks Warren *NM*

[Joe L.]

Re: Bairs rebuilt rear spindles seem too stiff ???

Michael-----

That's the best advice I've heard from you yet. I most certainly will continue to "do it my way" unless I become convinced that there is some error in "my way". Absolutely nothing that you've said convinces me of that. Plus, and I am 100% serious about this, I STRONGLY ENCOURAGE you to "continue to do it your way". Nothing could possibly make me happier and I mean that.

[Duke W.]

Re: Bairs rebuilt rear spindles seem too stiff ???

It's been awhile since I worked on a Corvette rear spindle pack, but a few years ago I adjusted the front wheel bearings on my '88 MBZ 190E 2.6 - didn't repack them - just adjusted front wheel bearing clearance chasing a small front end vibration.

The end play spec is .01-.02 mm. This is .0004-.0008" - four to eight TENTHS!

Needless to say measuring this with a dial indicator is difficult, but what I find on wheel bearings is that if there is ANY amount of clearance you should be able to "feel" it even with new grease and seals. If you grab the hub across various diameters and wiggle it, you should be able to feel even a few tenths clearance as long as the spindle is secured to either the vehicle or a bench vice.

The Merc spindle nut has a pinch bolt so the nut can be set at any arbitrary clocking, and I finally ended up tightening it until I could feel no play, then loosened it a hair until I could just feel some perceptible play. The dial indicator readings had too much variance to be conclusive.

I've also adjusted GM front wheel bearings to minimum clearance by filing the washer and tightening the nut 1/12th turn and inserting the cotter pin in the perpendicular hole to achieve about .001" clearance. For example if the clearance is .003, file the washer .002". Turning the nut 1/12th turn CW advances it .004" (1/20/12 = .00416) , so you end up with about .001" clearance. IMO tighter front wheel bearings yield more precise on-center steering, and it's worth the effort. Minimum end play it best, but it's tough to measure when you get down to a thou or less.

The bottom line is that if there is ANY amount of clearance you should at least be able to feel it.

My suggestion is to use an electric drill or air wrench to rotate the spindle at a few hundred RPM for a couple of minutes, which will squeeze out any excess grease, then check for clearance by feel. This is best done with the trailing armed secured in a vice as it's tough to secure on the car unless the halfshafts and strut rods are attached, and you should conduct this test before further assembly. The trailing arm needs to be firmly secured so you can feel even the tiniest amount of bearing clearance.

If after spinning the spindle as above I could not at least feel just the barest hint of play, I would be concerned.

Duke

[Warren L.]

Re: YES!! YES!! I AGREE!!

Joe I thought I read on the first post about a pry bar to measure bearings I shouild go back and re read but it is 2:30 am and I still want to go jogging, I have my priorities you know.

Iregardless of that I have read this site for three years and never once seen anyone talk about how to measure a tapered bearing correctly. I am a cabinetmaker and tbe furthest thing from a mechanic however when I do something I try and think it out and I find a pro or two or three and ask questions then follow what they say.

i reported that based on the Timken enginners and based on my friend who races. He had his machine work done by Ed Pink for his 911, put the motor together an dissassembled it six times and won first place in every race he put it in for three years so I trust him.

he looked at the spindles which had never done in his life then wrote a fomula, he neasureed the spindles and the bearings and calculated. It was subastantial, 1.5 or so but I would have to get the notes out of the file with his measurements scanned in cause I knew I would never remember this expeically back ten years ago now or whenever it was. Different measure for each time. We did the actual and it was all written down as well, sorry I can't open the file or I would and tell you the exact measures, not point in guessing.

Engineer said ther would be a loss, the best mechanic I have ever met said there would be a loss and wrote the formula down out of his head not out of a book and the dial indicator bore out completely there was a loss cause I tested it first on the spindle tool that the nice smiling salesman sold me at Carlise. It is not fairly tale stuff it checked out.

I am used to people telling me I am nuts more or less for suggesting this especially the guys who sell the tools, imagine that.

I am trying to remember and I do kind of think we did .0005 for both and then the grease was done from there. They turn fine. But what I did would be in the notes.

Engineers told me alot of stuff, some of it was pretty surprising.

Think about all the notss here on spindles, never seen anyone talk about making sure the race surfaces in the spindle housing were parrallel or the crush collar or tha the shims are parrallel. I did what they all said I never would have thought of or found my crush collar being out of parrallel, I thought GM did everything perfect and ehecking the bearings race housing in the spindle support was a good idea as well.

Too late for me to read your post and all the details, I read the first one up top then the one above my first post and just thought that unless the bearing is measured the way a taper bearing is supposed to be measured why are we talking about tolerances.

The differnce between measuring it right and wrong will and can be .003 to .004.

Will read your post beter tomorrow, if I said anytying that bothered you sorry I was reporting based on the first post I read and whatever it stated for measuring a tapered bearing it was wrong.

Warren

/

[Warren L.]

Re: YES!! YES!! I AGREE!!

For the handling aspect the amount of play at the spindle seems like diddly at .001, .002 or .003 or .004, at the outer edge of the tire where it contacts the road and if you want something to handle well like guys who race t becomes substantial.

I bet you do have feel the diffence when you work so dilligently on that clearance. Nore sure what model your car is but I liked those 90-92 560SEC's with tires wheels exhaust and lowered, too bad they didn't come with a standard. Know this old guy with 20 plus cars he had one and when I asked about it said it ran like a Roller only with way more power. A friend had to tell me a roller was a Rolls. Drove an SEC on the highway, what a joy, everything I ride in now I hear all the mechanical stuff turning and whining. That thing was like an anechoic chamber.

I would have liked to have measured what .002 say is at the outer edge of a tire just for interest sake.

Duke I did spin the spindle in my drill press, I put a slight pressure on it then ran it, the slight pressure for the drill press just made it easier than doing it by hand. We did it by hand as well with hand pressure and found it took 7-10 times under pressure to be sure, same results as the drill press.

Warren

[Joe L.]

Re: YES!! YES!! I AGREE!!

Warren-----

Yes, you don't have to worry about your memory regarding the pry bar; a pry bar was discussed earlier in this thread. However, what I was pointing out was that the use of a pry bar was never a GM-recommended part of the procedure. It's a "field improvization". So, whether a pry bar's use in moving the bearings to check end play is right or wrong, we can't blame anyone at GM for it.

[Joe L.]

Re: Bairs rebuilt rear spindles seem too stiff ???

Duke-----

As I've mentioned previously in this discussion, I totally agree that you SHOULD be able to feel/measure end play if there is any, with or without grease. That's what I used to believe, too. That's why I went through so many repeated trials (at GREAT expense of time and effort) after setting the end play at .001-.002" dry and then finding that I could not feel or measure any after I packed the bearings and assembled. If I had believed that it was ok for there to be no perceptible bearing end-play after packing the bearings, I could have saved myself a lot of time and effort.

However, what I found after MUCH trial and error, much work, and a lot of discussion with folks that have done this professionally for years is that when the bearings are set at low clearance dry, it's often difficult to detect or measure any end-play after the bearings are packed and the unit assembled. I don't know the reason for this. It doesn't seem reasonable to me; it never has. But, that's what I found after going through this MANY times. As I mentioned, this is not an opinion; it's what I OBSERVED under the procedures and conditions I described.

One set of trailing arms that I did this way I used for over 50,000 miles. They always woried me, though. Finally, I decided to do them again since "I was sure there was a problem and the bearings were going to go out on me". When I disassmbled them, everything was PERFECT.

By the way, after a few thousand miles of use, you CAN measure an end play with the bearings as-is and packed. The end play I measured then? Right at what I originally set them at DRY. Why? I have no idea.

[Warren L.]

Re: YES!! YES!! I AGREE!!

Thanks joe, I am going fast and I miss stuff, it was neat to learn about all this from the people I asked to teach me, it even helps me in my cabinet shop from time to time, like setting the knives on the SCM planer with the dial indicator, easy to get them accurate to 001, machine cuts better when all there are doing the same thing.

I take back my statement about the GM moron I think I was thinking about the developer who built a home behind me and cut the roots on my 65 foot tall trees, feeder and anchor roots all gone. I have to wear a crash helment when I am in my back yard now.

Warren