Dial Indicator Confusion - PeachParts Mercedes-Benz Forum

#1 08-24-2002, 02:45 PM

Searching for a dial indicator to check run-out. Am confused on which to buy for checking wheel run-out.

The ranges are:

0 - .5" x .001
0 - 1" x .001

.25" x .0005

.50" x .0005

.05 x .0001

These are from a Grizzly Catalog and don't know much about them as I have never used one before. Always ready to buy a new tool. Have checked ebay and saw many on there made by Starllet, Brown and Sharp, Chicago Tool. Which is best for this application?

Gympie

leathermang · #2 08-24-2002, 03:32 PM

How close are the tolerances which you need to measure ? Are you going to be using it on a regular basis ? Do you do machining work which it needs to be used for also ?

In general the 0-1inch .001 is a very common size for all purpose work... few people can get closer than .001 on the items they are making... and that is the accepted standard for "home shop machinists"....mostly because most lathes will not hold tighter than that.....due to the head bearings/ the alignment of the chuck... and flex of the tool and carriage......

Harbor Freight has 0-1 , .001 dial indicators on sale now in Austin for about $7..... so I picked up an extra just for grins.... but my Mytutoyo (spelling?) cost about $18 and the magnetic holder about the same...Just be sure they are AGD ( or something like that certified.... I don't know of any that are sold which are not.. but thought I would mention it... the Harbor Freight are also...

I am not sure which measurement you are wanting to check... are you going to chuck it up.. or measure it on the spindle ? I think technically , to be correct , you must take out the bearings and hold it tight on a good tight bearing head...

some of these measurements can also be made with an actual straight edge and feeler gauges.... or with a jig held solid and the wheel rotated under it using the feeler gauges... cheaper but not as much fun as the dial indicator... If you measure with the tire and wheel on you are measuring the combination of the bearings, the rotor, and the wheel....

Check out the Bass Tool catalog from the guys in Houston... and the Msc catalog for comparisons....

I will correct the spellings and abbreviations in this when I can find the info...

Mark V · #3 08-24-2002, 03:34 PM

I assume you're talking about rotor runout. If so the 0-.5 x .001 will give you all the range and resolution you need.

leathermang · #4 08-24-2002, 03:39 PM

There are other fun things both on your car and in life which a dial indicator come in handy for... and the cost difference is not much (if any) between the half inch and the one inch...and since we are talking about the same resolution I would suggest the one inch...

#5 08-25-2002, 12:43 AM

Thanks all for your help and suggestions. Will be using it to measure wheel bearing end play, which is .01-.02mm tolerance and disc lateral runout, max. .12mm.

Next step is to get the race's out. Have read in the archives that a chisel punch will do the trick. Will give it a try, but am skeptical. Wish indents were placed in the hub to remove the race.

Can anyone recommend a certian driver to get the bearing and seal set?

Thanks again,

Gympie

leathermang · #6 08-25-2002, 08:40 AM

If you always think and act in MM then it would be more fun to have a dial indicator with a MM face on it....they do make them...

Although it is not available the FIRST time you do it... saving the OLD race and grinding about .001 off the edge will make a great removal tool for the next time... I always save old races ... then weld a suitable handle to it... very fast and easy from then on... but the chisel should work fine the first time... just go evenly around the edge.... well... I mean skip around the edge in about three places with small hits to drive it out as straight as possible... getting it cranked sideways really increases the pressure needed to get it out...so slow and even it the key...

When you do get it out... I wonder if there would be anything wrong with using a small grinder and making indents for the future... they are nice to have....

psfred · #7 08-25-2002, 11:31 AM

I use a soft punch to drive out wheel bearing races. You need a fairly long one, as you must reach through the hub to catch the back side of the race, it sticks out from the bore. Use a fairly large hammer (I usually use a 2lb sledge) -- gravity works better than my puny arm muscles.

Just tap firmly all around the rim of the race -- as leatherman said, it will only come out straight on, if it cocks in the bore, the force required to move is is more than you can generate with a hammer.

The reason for a soft punch (readily available at hardware stores or autoparts stores) is that bearing races are VERY hard, and hence fairly brittle. A sharp, hardened punch will cause very high stress at the impact point, and you risk cracking or fracturing the race, and then it will tend to gouge the hub, making drive the new one in difficult, to say the least. Also, if you slip, a soft punch won't gouge the hub, either. The soft punch won't bounce off the rim as easity, either.

Since I slipped off the race many, many times learning to do this, I stay with a soft punch! I don't replace wheel bearings often enough to stay in practice!

Peter

leathermang · #8 08-25-2002, 12:16 PM

Peter, I kept waiting for the punch line..... can we say " Brass equals 'Soft '" ?

#9 08-25-2002, 12:50 PM

Boy am I happy I read your replies to my message before going out and hammering on the race! Was going to use a cold chisel on it, but now thanks to your reply, will go and get a brass punch instead. Thanks a million.

Once the race is out I will save it for future removals. Just sorry I don't have one now. Great tip. Went to a tool rental place yesterday to rent a hub remover. Asked the owner if he had a tool to remove the race. He said he did not but would call a friend who works at Brakes Plus. His friend said they won't work on a MB race and sends them to a MB dealership to be removed. Didn't know dealerships did this for shops.

Good idea about making indents in the hub for future removal. A web search came up with the same problem in Mazdas. This link provides a way to place the indents in their hubs. But they have aluminum hubs: http://www.mazdatrix.com/faq/frontbrg.htm .

If I may ask another question. The 10mm hex bolts which hold on the disk are pretty tight. Don't have a vice large enough to hold the hub adequetly. Do you suppose a impact wrench would work on this using a 10mm deep socket and a stub 10mm allen?

Thanks again guys, good day

Gympie

psfred · #10 08-25-2002, 12:58 PM

Brass works, so does mild steel. Just stay away from hardend punches.

Getting the rotors off without a vice will be a pain. The bolts are usually locktited in (for good reason!), and we break them loose with a hammer impact before going at them with a long breaker bar.

You don't need a huge vise -- just find a way to hold the rotor so that most of the leverage is applied to a stationary part.

Air impact works the best, of course......!

Peter

#11 08-25-2002, 01:26 PM

Thanks Peter.

The MB service manual states that the hex bolts are not to be reused and ordered new ones. Looks like they have a coating of Blue Loctite on them. Guess the removed ones can be used again if a coating of Loctite is applied. I didn't order new caliper bolts, but will use Loctite upon installation.

The service manual states to remove the rotor by placing 3 M12X1.5 bolts in the hub and placing it in a vice. Guess the boltse used to protect the hub while crimping.

Thanks again,

Gympie

leathermang · #12 08-25-2002, 03:32 PM

In some situations you might want to take the rotor off without dealing with the wheel bearings... like a simple rotor replacement...or not have air power available....

In that case you can get an old steel wheel and weld a pipe to it which will lay on the ground... typically about 3 feet long... and drill holes for access to the allen head bolts ....

Then you can take off the wheel, secure the hub, and use a good long cheater bar ... like 4 to 6 feet to break them loose....you place it to the left on the ground when you are loosening them and you are on the left also.... so your torque is going between you and the ground... otherwise you will be lifting the wheel.... then reverse the side the arm goes on and that you are working on when putting them back on....

This was about the only way I could get the rear axle nut off old VWs.... it just ignored my 1/2 inch impact ... remember, 200 lbs at 5 ft is 1000 lbs of torque...... don't strip stuff out when putting it back together... use a torque wrench if you have one... or you can measure some distance on the cheater bar and hang the correct weight on it to get it right....

And concerning impact drivers.... always use impact sockets,extensions,adapters , etc that are designed to be used with impact drivers... and use goggles to protect your eyes even then......

Peter, on the chisel I was just figuring most people would not be able to look at a steel punch or chisel and tell whether it was hardened or not... so safer to recommend brass I figured...

#13 08-26-2002, 01:08 AM

Thanks leathermang for the reply.

Hey, that is quite a rig you came up with to remove the allen bolts for sure. Went out and bought a vise this afternoon, any excuse to buy a tool eh? Think I'll give that a try before I find another excuse to buy a welder. :-)

Thanks for the safety tip on the impact driver. Yep, know about the hazards of not using the correct equipment properly. Saw a guy once nearly take a piece of socket shrapnel into his eye by not using a impact socket.

Will work on the 280S in the morning and keep you advised. Appreciate your help and attention.

Gympie

#14 08-27-2002, 01:01 AM

As an update to getting out the wheel race.

Would like to thank Peter and Leathermang for their expert help and advise. A punch and ballpeen hammer did the job in less than .5 hours for both wheels. Might add although to advise the same method but be sure to keep the punch face squared off by filing and take off the rounded edge. Otherwise works like a charm. No need for a special MB tool to do the job. A Do it yourself job for sure. I'll save the race's for a future job now.

Thanks again guy's!

Gympie

leathermang · #15 08-27-2002, 01:24 PM

Glad to hear that it turned out well....