front hub runout

D

Doug

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Joined
May 19, 2012
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33
Need some ideas.
I checked the runout on the front hubs before I fitted the new rotors and found they had about .014 runout on each side. (on new wheel bearings) Removed the hubs and took them to be machined. The guy doing the work removes the bearing case and centres the hub on the machined section of the hub were the bearing sits. When he checked them he said that they are running true. How can I have .014 on the car and none on the lathe.

Any ideas on what the problem could be.


Doug
 
Bottom line, the runout you have with bearings installed and set properly on the spindle, will give you your true runout.

Don't know how he set it up on his lathe, can't really imagine being able to easily do it without being able to chuck both the races at once. Chucking on just one land would be hit and miss.
I would take it to someone that knows what they're doing on a regular brake lathe in GOOD shape that centers on the outer races. A slow, fine, final cut should get you real close.
 
I couldn't figure out how he could do it accurately like this either, but he came recommended and the Brake shop outsorces these jobs to him. I will try to get them machined on the car, just like to be sure I'm not masking another problem.


Doug
 
On the car? Did you measure the runout on the rotors or on the hub itself ? The machine shop measured the hub and not the rotor ?

Tap the rivet holes and bolt the rotors to the hubs, measure runout again. If runout is bad, rotate the rotor over one hole, measure again....

Maybe the rotors need some fine tuning on the inner mating surface to make it run true ....
 
The .014 runout is on the hub, It was a lot more with the rotor bolted up. Checked the rotor in all 5 locations and got very little change. I havn't taped the rivet holes but I did fit the rotors with all 5 wheel nuts when I checked them.
I'm not convinced that the way he mounted them in the lathe was the most accurate way to do it, but I will drop in and talk to him tomorrow and see what we can work out.


Doug
 
Something is not right. If the hub mounted on the lathe arbor reads true and the hub really has .014 runout, the arbor would have to have EXACTLY the same runout AND the hub would have to be put on the arbor co-incidendal with the runout. That is a chance in a million.

To check the trueness of the arbor. Measure the hub and then turn the hub 180 degrees on the arbor. If you get the same reading, the arbor is running true.
 
Picked up the hubs today and had a chat to the machinist. He said the only way he could get them done accurately was to turn up a shaft identical to the stub and install the hub complete with the bearings and then turn it. I wish he would have said that in the first place, then I would not have had to pay for having no result.

Will check some other brake shops next week and see if someone can turn them on the car. The joys of old cars.


Doug
 
I assume you have all the studs out of the hubs.
Here's what I would do.
-tap all the rotor mount holes
-mark and index each hub and rotor with each other using a stamp or grind some light marks, something permanent
-install all the bearing races
-find a brake shop that has a regular brake lathe in good shape, not a machine shop engine lathe and preferably an older experienced guy that is will to take the time to do it right
-you may want to take along your dial indicator setup
-after he cuts the hub, mount the rotors with the your screws and check the run out on the lathe without ever having removed the hub
-if they aren't acceptable then, then cut the rotors
-there should never be a need for you to ever separate the front hubs and rotors again until replacement

Almost all vehicles from the 60's to mid 80's had 1 piece front hubs and rotors and this is the way they were all cut. Never had any runout to speak of.

The rear is the problem setup. I would save the "on car " turning just for those.
 
010752 said:
I assume you have all the studs out of the hubs.
Here's what I would do.
-tap all the rotor mount holes
-mark and index each hub and rotor with each other using a stamp or grind some light marks, something permanent
-install all the bearing races
-find a brake shop that has a regular brake lathe in good shape, not a machine shop engine lathe and preferably an older experienced guy that is will to take the time to do it right
-you may want to take along your dial indicator setup
-after he cuts the hub, mount the rotors with the your screws and check the run out on the lathe without ever having removed the hub
-if they aren't acceptable then, then cut the rotors
-there should never be a need for you to ever separate the front hubs and rotors again until replacement

Almost all vehicles from the 60's to mid 80's had 1 piece front hubs and rotors and this is the way they were all cut. Never had any runout to speak of.

The rear is the problem setup. I would save the "on car " turning just for those.
Click to expand...

Thanks for the info, that sounds like a good way to try. I dropped the hubs off at another shop and the old guy there explained to me how he could do the hubs. Will get them back tomorrow and re-check on the car, if all is good then I can bolt up the rotors and see how they run. Only problem is, the rotors are drilled and they ca sometimes have trouble with chattering when they turn them. Will see how it goes tomorrow. Thanks again, appreciate your help.

Doug
 
Doug said:
Need some ideas.
I checked the runout on the front hubs before I fitted the new rotors and found they had about .014 runout on each side. (on new wheel bearings) Removed the hubs and took them to be machined. The guy doing the work removes the bearing case and centres the hub on the machined section of the hub were the bearing sits. When he checked them he said that they are running true. How can I have .014 on the car and none on the lathe.

Any ideas on what the problem could be.


Doug
Click to expand...
Did you have excessive runout before you replaced the wheel bearings? What is the "bearing case" you say he removed before he checked the runout? Not that I agree with his measuring technique, ff you mean the race maybe the race was not seated correctly or the race is the issue causing the runout.
 
Well I never had to face a front hub and don't recommend it. I wonder if he held it on the ID of the bore with a 3 jaw chuck?

On the other thread I mentioned using 3 jaw chucks and 4 jaws. I just did a set of T/A's this week so since we were talking about this subject this week I chucked up the original rear spindles in a 3 jaw. Then I used an indicator on the lathe cross slide and carriage to come in and zero in the indicator. The flange runout was 015", then I installed a new in the box USA spindle and that was 008". I know full well the runout was in the chuck and did not face the flanges, I would have created more runout then I had for sure. When I finished the spindle install I installed the rotors and checked them, these are not the originals but newer aftermarket. They were out 012 on one and 005 on the other. I dialed the 012 to 0015 and the 005 to 002 by using 002-007 shims and bolting them on. The rotor is tight on the spindle, no gaps between it and the flange, and dialed in.

Bottom line is that is what works for me. For your fronts I would have just dressed the hubs at the rivet holes,since the rivets will pull up the iron around the holes. Then I would set it up on the spindle, held in a vise, and set the bearings up. Then install the rotor, bolt it on and then check the runout and address that. If the hub flange has been faced it may be way off now. Before I would attempt to cut it again see where the runout is once the rotor is back on and the bearings setup.
 
I have faced quite a few front hubs that were cupped and would have high spots in 2 or 3 places. I have always done it in a 3 jaw lathe with a live center and a brass arbor that mates with the beariing taper. Never had any problems facing a hub.
 
Hey guys, thanks for all the input.

Sky65; No I didn't check the runout before I replaced the bearing, wish I had now. Yes I did mean the inner bearing race. He used an internal chuck were the race seats in the housing. I'm also confident that the race was seated correctly when I did the bearings, if it wasn't or if there is a problem with the race, I think I it would have shown up when I adjusted the bearings but they felt fine.

GTR; You need to come over here and set up a shop. The reason I felt I had to have the hubs faced is that the runout I measured on the car was .014 and the original rivets had definately pulled the material around the holes. The metal around the wheel studs was also slightly raised. On the left hand side there was also a very pronounced raised ridge on the outer edge of the hub that would have interfeared with the rotor seating correctly.
I did bolt the rotors on before I pulled the hubs back off,and checked to see what the runout was and I got a reading of around .025, and there was very little change when I clocked them. I thought this was way too much to either shim out or have machined from the rotor. I thought that by truing up the hubs, it would give me a better base to start from. I have no issue with shimming the rotors but I would not be comfortable trying to shim that much runout. Will get the hubs back tomorrow so hopfully I made the right choice.

Thanks again for your help guys.
Doug
 
Doug,
Yes 025 is too much to shim, IMO. The most I worked with was 015" and got it down to 002" so in that case I too would have dressed the hub,but only if cleaning the area around the holes didn't work.
I'm sure you will get it, it's not rocket science to use a extremely overused expresssion!

That one rear spindle I just dialed in that was 012 I thought might give me a problem. Someone hit it a couple of times with a center punch but I still saw the factory facing so I went with it. If it had been out much more I would have had to break it down and then face it.

FYI- when I build a 12 bolt I also have to machine the posi flange and dial it in with the 3 jaw but use a large live center and it usually dials in to 001 or less. Never had Ring Gear runout more then 002 over 360*.

Good luck
 
Well I got the hubs back today and fitted them up, checked the runout and got .012. Wandered around the shed ranting like a madman wondering what I do now. Pulled the hubs again and checked that I had everthing right, put them back on and checked runout again, same reading. More swearing.
Then I happened to find the problem. Some IDIOT was using the wrong guage. I picked up the Metric guage by mistake. In my defence they acually do look the same. Anyway, the reading was really .012 millimetres, which is approx .0005 ins. Hereby nominate myself for the Dumbass of the year award. At least I know now that the hubs are spot on.

Thanks again to all that tryed to help, sorry for wasteing everyones time.

Doug
 
Doug said:
Well I got the hubs back today and fitted them up, checked the runout and got .012. Wandered around the shed ranting like a madman wondering what I do now. Pulled the hubs again and checked that I had everthing right, put them back on and checked runout again, same reading. More swearing.
Then I happened to find the problem. Some IDIOT was using the wrong guage. I picked up the Metric guage by mistake. In my defence they acually do look the same. Anyway, the reading was really .012 millimetres, which is approx .0005 ins. Hereby nominate myself for the Dumbass of the year award. At least I know now that the hubs are spot on.

Thanks again to all that tryed to help, sorry for wasteing everyones time.

Doug
Click to expand...

Don't feel bad, at least you got it right in the end
 
Doug
Don't worry we all have been there and will be again. Sometimes I walk away from a problem and find it works out better then next day.

Sounds like you are all set now so go ahead and setup the bearings and rotor!
 
He set it up with a tapered block on each end, seating on the bearing races, and a shaft through the centre. Seemed to work fine.


Doug
 
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