Rear Wheel Bearing Interference Fit |
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Rear Wheel Bearing Interference Fit |
wndsrfr |
Jul 24 2011, 07:09 PM
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#1
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Senior Member Group: Members Posts: 1,429 Joined: 30-April 09 From: Rescue, Virginia Member No.: 10,318 Region Association: MidAtlantic Region |
So, now with the trailing arm off & old bearing out & new timken in freezer I started to measure with my digital calipers & get:
Trailing Arm recess=2.950" room temp (95F today) Bearing O.D. =2.9525" cold (maybe 20F) Interference = .0025" Is 2 1/2 thousandths OK? I'll heat the trailing arm recess prior to installing, but bet I'll only gain maybe a thousandth, leaving 1 1/2 thou interference for the press to overcome.... But, the next question is more disturbing...the hub to ID of the bearing is: Hub O.D. = 1.6520" warm Bearing I.D. = 1.6475" cold Interference = .0045" Of course I've put the hub into the freezer and will wait for the bearing to come to room temp prior to assembly, but I'm guessing I'll still be dealing with .003" interference there and that seems like a lot....need someone with bearing fit tolerances to chime in here.....anyone? |
sixnotfour |
Jul 24 2011, 08:24 PM
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#2
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914 Wizard Group: Members Posts: 10,430 Joined: 12-September 04 From: Life Elevated..planet UT. Member No.: 2,744 Region Association: Rocky Mountains |
When is the last time your calipers were calibrated ?
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underthetire |
Jul 24 2011, 08:24 PM
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#3
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914 Guru Group: Members Posts: 5,062 Joined: 7-October 08 From: Brentwood Member No.: 9,623 Region Association: Northern California |
No matter what calipers you get, they are only good for +/- .001. Since you are using the jaws on the Id of one, and the od on the other, I wouldn't trust your measurements. If you have standards to check your calipers, might want to do it. See if one of your local guys has a mic set and good starett telescoping gauges.
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SLITS |
Jul 24 2011, 08:26 PM
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#4
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"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None |
I never heated the trailing arm installing bearing. I froze the bearing, applied a coat of lithium grease, pushed it into the housing while still cold. Used a 1/4" flat plate to drive it in and seat the bearing flush.
Pulling the hub through the bearing, I used a homemade tool from all thread, spacers that supported the back side of the bearing and pulled it in. Never worried about interference fit. This is automotive stuff, not aerospace and the tolerances allowed are like shooting the side of a barn with a blunderbuss. |
sean_v8_914 |
Jul 24 2011, 08:42 PM
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#5
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Chingon 601 Group: Members Posts: 4,011 Joined: 1-February 05 From: San Diego Member No.: 3,541 |
thats funny...but true.
fat peice of steel and a dead blow (shot filled, plastic outer) hammer. I heat the arm and drive it in liike Ron described above. its not that hard. just keep it going in STRAIGHT. |
PRS914-6 |
Jul 24 2011, 09:44 PM
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#6
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Excellence Magazine Project 914 3.6 Group: Retired Members Posts: 1,278 Joined: 20-May 06 From: Central California Member No.: 6,031 Region Association: None |
The "proper way" would be to use a hydraulic press and only press on the outer race. Beating them in may get you there but it's a hack job. The difference between the height of the inner race and outer race is minimal and a 1/4" plate would most like flex enough with a firm blow to contact the inner race and to the balls. Given a choice, I would heat the arm before I would beat on the bearing. However, I would be lying if I said I never beat in a bearing (IMG:style_emoticons/default/biggrin.gif)
The proper way...... |
draganc |
Jul 24 2011, 10:27 PM
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#7
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Senior Member Group: Members Posts: 725 Joined: 2-November 09 From: central new jersey Member No.: 11,000 Region Association: North East States |
I never heated the trailing arm installing bearing. I froze the bearing, applied a coat of lithium grease, pushed it into the housing while still cold. Used a 1/4" flat plate to drive it in and seat the bearing flush. Pulling the hub through the bearing, I used a homemade tool from all thread, spacers that supported the back side of the bearing and pulled it in. Never worried about interference fit. This is automotive stuff, not aerospace and the tolerances allowed are like shooting the side of a barn with a blunderbuss. (IMG:style_emoticons/default/agree.gif) i had my bearings in the freezer for about 2 weeks. cleaned the inside of the trailing arm with scotch brite and applied a thin coat of grease. it took only some light tapping with the rubber mallet. |
sean_v8_914 |
Jul 25 2011, 07:14 AM
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#8
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Chingon 601 Group: Members Posts: 4,011 Joined: 1-February 05 From: San Diego Member No.: 3,541 |
I have done many of these. it only takes some tapping. its not a hammer-fest. they go in easy.
removing the trailing arm is a waste of time. there are many times when using a hammer is OK if one is not beligerent about it. using a press does allow you to stick out your pinky while doing it :"the proper way" |
wndsrfr |
Jul 25 2011, 07:27 AM
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#9
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Senior Member Group: Members Posts: 1,429 Joined: 30-April 09 From: Rescue, Virginia Member No.: 10,318 Region Association: MidAtlantic Region |
No matter what calipers you get, they are only good for +/- .001. Since you are using the jaws on the Id of one, and the od on the other, I wouldn't trust your measurements. If you have standards to check your calipers, might want to do it. See if one of your local guys has a mic set and good starett telescoping gauges. Yep, you're right about the positioning of the jaws....lots of error available there, which is why I use the technique of multiple, multiple measures with constant light pressure on the thumbwheel and only recording the highest on ID or lowest OD reading. Also, the absolute measurement isn't the point or to be trusted, it's the relative measurement that's useful as I took these readings back to back with the pieces right next to each other. Even though it's a cheapo digital, I'd stack up the relative measurements against any other instruments within the tolerances we're looking at.... That said, taking your advice about error in the positioning, with both pieces cold this morning I got .0015" intereference on the bearing ID to the hub OD...looks OK to me.....on to the assembly! |
PRS914-6 |
Jul 25 2011, 08:13 AM
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#10
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Excellence Magazine Project 914 3.6 Group: Retired Members Posts: 1,278 Joined: 20-May 06 From: Central California Member No.: 6,031 Region Association: None |
removing the trailing arm is a waste of time. there are many times when using a hammer is OK if one is not beligerent about it. using a press does allow you to stick out your pinky while doing it :"the proper way" He said the trailing arm was already off..... (IMG:style_emoticons/default/confused24.gif) I don't see the logic in suggesting to the man to beat on a bearing with a hammer which is the method most likely to damage a bearing when he has the arm in his hands...... A threaded rod is another alternative if on the car. If beating on a bearing works for you that's great, I guarantee you will never find that method in a repair manual. However, when people come here asking for help I think it's important to at least provide them with methods best suited for success as well as the lesser desirable methods if you don't have the proper tools.... Take a look on the Bird Board and you will find thread after thread of people having issues after beating bearings in and out. My worries are this.....People in the future do a search and find a thread like this and all they see is the hammer method. Haven't we done them an injustice? Yeah, my pinky is out but I'm not ashamed....I'm just trying to help people that are asking for help... |
Jeffs9146 |
Jul 25 2011, 10:27 AM
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#11
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Ski Bum Group: Members Posts: 4,062 Joined: 10-January 03 From: Discovery Bay, Ca Member No.: 128 |
QUOTE He said the trailing arm was already off..... I don't see the logic in suggesting to the man to beat on a bearing with a hammer which is the method most likely to damage a bearing when he has the arm in his hands...... A threaded rod is another alternative if on the car. (IMG:style_emoticons/default/agree.gif) The all thread method is way better than a hammer! I have bearing press plates that come in 6 different sizes and I took a large washer that I ground to fill in the final edge of the bearing! By using the press plates and the washer it eliminated any flex that may have pushed on the inner race. Once you have the all thread in and the edges of the bearing started you can switch to air tools to finish pulling the bearing in! I have done this 6 or 7 times with no problems! (IMG:style_emoticons/default/beerchug.gif) |
6freak |
Jul 25 2011, 11:20 AM
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#12
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MR.C Group: Members Posts: 4,740 Joined: 19-March 08 From: Tacoma WA Member No.: 8,829 Region Association: Pacific Northwest |
Bearings and a hammer (IMG:style_emoticons/default/WTF.gif) .....if you force it in the balls will not have room to rotate .... ....Arbor press is the best ...you can feel things moving ,,unlike a hydrolic press....JMO..I have replaced thousands of bearings in my 23 years here at the B*$#@g company and have not one failer .....dont get in a hurry use the proper tools and for god sakes put the hammer down...even the slightest damage to a bearing or race will reduce its life by half if not more ...good luck with the project ....again JMO
NSK has some good info on there web site with pixs http://www.nskamericas.com/cps/rde/xchg/na...ml.........look up fractures ...thats what you will be doing to the bearing when you strike it with a hammer |
Eric_Shea |
Jul 25 2011, 11:30 AM
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#13
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PMB Performance Group: Admin Posts: 19,275 Joined: 3-September 03 From: Salt Lake City, UT Member No.: 1,110 Region Association: Rocky Mountains |
Proper way is to press the arm down onto the bearing... (IMG:style_emoticons/default/biggrin.gif)
http://www.youtube.com/watch?v=T6CxhlpOvng https://www.youtube.com/watch?v=T6CxhlpOvng |
SUNAB914 |
Jul 25 2011, 12:11 PM
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#14
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Senior Member Group: Members Posts: 698 Joined: 29-December 08 From: Fredericksburg VA Member No.: 9,880 Region Association: South East States |
Another proper way, freeze bearing, put grease outside edge and place a 2x4 on it and beat it in. Done.
as stated before - keep straight. |
mgphoto |
Jul 25 2011, 12:16 PM
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#15
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"If there is a mistake it will find me" Group: Members Posts: 1,339 Joined: 1-April 09 From: Los Angeles, CA Member No.: 10,225 Region Association: Southern California |
Picked up this kit last year, works with the hubs on the car, using only wrench effort, removing and installing.
http://www.sirtools.com/hub_kit.htm |
6freak |
Jul 25 2011, 12:50 PM
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#16
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MR.C Group: Members Posts: 4,740 Joined: 19-March 08 From: Tacoma WA Member No.: 8,829 Region Association: Pacific Northwest |
looks like a nice set ....wish i had one like that ...I just to set the record strait i destroid a bearing in my 914 I purchase from PMB by not using the proper tools ...it cost me time and a new bearing ...again take your time and good luck
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SirAndy |
Jul 25 2011, 01:14 PM
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#17
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Resident German Group: Admin Posts: 41,640 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
My worries are this.....People in the future do a search and find a thread like this and all they see is the hammer method. Haven't we done them an injustice? Yeah, my pinky is out but I'm not ashamed....I'm just trying to help people that are asking for help... (IMG:style_emoticons/default/agree.gif) Using a hammer is asking for trouble ... (IMG:style_emoticons/default/shades.gif) |
wndsrfr |
Jul 26 2011, 09:06 AM
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#18
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Senior Member Group: Members Posts: 1,429 Joined: 30-April 09 From: Rescue, Virginia Member No.: 10,318 Region Association: MidAtlantic Region |
So, now with the trailing arm off & old bearing out & new timken in freezer I started to measure with my digital calipers & get: Trailing Arm recess=2.950" room temp (95F today) Bearing O.D. =2.9525" cold (maybe 20F) Interference = .0025" Is 2 1/2 thousandths OK? I'll heat the trailing arm recess prior to installing, but bet I'll only gain maybe a thousandth, leaving 1 1/2 thou interference for the press to overcome.... But, the next question is more disturbing...the hub to ID of the bearing is: Hub O.D. = 1.6520" warm Bearing I.D. = 1.6475" cold Interference = .0045" Of course I've put the hub into the freezer and will wait for the bearing to come to room temp prior to assembly, but I'm guessing I'll still be dealing with .003" interference there and that seems like a lot....need someone with bearing fit tolerances to chime in here.....anyone? okay new bearing is pressed in new hub pulled in all installed nut tightened all to hell and everythings real good no play at all. Play time!!! |
SLITS |
Jul 26 2011, 12:18 PM
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#19
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"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None |
Picked up this kit last year, works with the hubs on the car, using only wrench effort, removing and installing. http://www.sirtools.com/hub_kit.htm Nice if you have $400 to blow the last time I looked for doing bearings about once every two years. |
rjames |
Jul 31 2011, 12:47 PM
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#20
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I'm made of metal Group: Members Posts: 3,933 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest |
QUOTE Another proper way, freeze bearing, put grease outside edge and place a 2x4 on it and beat it in. Done. as stated before - keep straight. No beating/tapping required. if you freeze the bearing and apply a thin coat of grease into the arm the bearing will just slide right in all the way. |
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