bearing replacement, shimming

[ziggy]

regaurding the upper. i'm gonna replace the bearings in my 1 drive for the drive shaft. the ones on my drive gear yoke. i understand that i will have to shim the drive gear. question to me is. will i need to shim the upper drive shaft? do i need to check the rolling torque of the upper drive shaft (driven gear)? or can i assume that it is set up proper? i will be useing the old gears, both driven and drive, as they seem to be servicable. replaceing the brgs because they're blue and the blue wont come off. i understand that if there's a question about a brg. any question. it should be replaced. that's why i'm doing the brgs.

in my previous posts, folks have talked about rolling torque on the drive gear too. setting the bearings proper. i have the small spacer in my drive and have ordered new spacers to go along with the new brgs. i just want to confirm. i don't do rolling torque on them when useing the spacers? is that right. just torque it down to 85 ft lbs while turning the brgs?

previous post over this same matter.....

http://forums.iboats.com/showthread.php?t=228998

http://forums.iboats.com/showthread.php?t=229200

i'm having to much time on my hands while parts are on order......thinking of possible questions. and the 2 questions above are naggin at me..... mostly the one about the upper drive shaft (driven gear) rolling torque. basicly i ain't gonna do nothing to that shaft is my notion... is my notion outa line?

 

[achris]

Re: bearing replacement, shimming

All of your questions are answered in the service manual. You do have a service manual, don't you?

If you're replacing the bearings, then the new ones need to be set up using the rolling torque method. As for the height on the driven gear, if you're reusing the gear and it's bearing, then it should be at the correct setting. That said, when I strip a box, I always recheck the height and preload on the driven gear. Never know what clown has been in there before me. You will also need to check and adjust the drive gear shims as well, because you're putting new parts in that sub-assembly.

Chris.................

Edit : Finally beat you to one Bond-o

 

[Bondo]

Re: bearing replacement, shimming

Edit : Finally beat you to one Bond-o

Ayuh,........ Top of the Morning, err, Evening to ya my friend,............

I tend to defer these kinds of Questions to yourself or Don, or others who Do these things,......
I just send Mine up the street to a Bud,.....
He works so Cheaply,.... I can't afford to buy the tools..........
I'd rather just supply his Beer Money,........

Besides,..... I've got Enough to do,+ as I age,...
I'm Finally realizing that I just Can't do Everything Myself.........

 

[rodbolt]

Re: bearing replacement, shimming

myself I dont sweat minor stains.
if its pitted then I replace them.
however if all your replacing is the input bearings all you have to check is for proper gear lash. there is a tool for it called a feeler gauge, I try to check lash and gear depth prior so I can place the tooth contact pattern the same when reusing gears. as far as torque or rolling torqe thecorrect method is in your manual with pictures. it depends on the bearing design and out of memory I cant say which is which.
its not hard but if your gonna reuse the gear try to place it back in the same orientation as it was with the old bearings. gears dont like changing wear patterns.

 

[ziggy]

Re: bearing replacement, shimming

You do have a service manual, don't you?

yep, 1,2,3,4 and 6..... i have read the service manual till i'm tired of reading it...

If you're replacing the bearings, then the new ones need to be set up using the rolling torque method.

from page 6A-20. item 7 service manual #2

7. Place one end of suitable bar in vise and other end through universal joint yoke for holding. Place bearing retainer nut, drive gear and bearing assembly onto universal joint assembly. Place washer (concave side facing drive gear) and nut on universal joint shaft. Be sure that preload spacer is centerd and does not protrude past bearing cups. Torque nut to specifications while turning bearings. NOTE: the torque on the universal joint shaft nut applies correct preload on drive gear bearing assembly. Make sure that torque is correct.

that statement is why i'm asking about the rolling torque on the brgs on the drive gear yoke when i assemble the new brgs onto it.

As for the height on the driven gear, if you're reusing the gear and it's bearing, then it should be at the correct setting. That said, when I strip a box, I always recheck the height and preload on the driven gear.

i suppose is the key word there is "should". i would like to check that rolling torque. lake of a proper inch lb torque wrench is what's stopping me. from the other posts, i've not had any gear or brg problems. i'm this far into the upper because of water intrusion and rusty ujoints. i wanted to check the ft seal.....this drive did hold 15psi prior to tear down. i believe end of year maint. saved me from haveing major issues, like water in the drive. which i didn't have.

i like yer idea bondo, but i don't have any friends that do this for a living. i did get the dealer to offer to let me use their shim tool though.

rodbolt,

if all your replacing is the input bearings all you have to check is for proper gear lash.

yes, that's what i'm up to.

I try to check lash and gear depth prior so I can place the tooth contact pattern the same when reusing gears.

that i didn't do. however i got the 1:65 ratio, with hash marks. though i've not seen the driven gear mark yet as i aint got the top cover off yet....i assume it's there. i appear to have 2 marks on my drive gear. hopeing to get it back the same way because i got the marks....

 

[rodbolt]

Re: bearing replacement, shimming

Like I said, the correct method of torqueing the pinion nut depends ENTIRELY on the bearing design. one uses a rolling torque the other a straight torque.
out of memory I cant say which is which its up to you to determine which design you have and use the correct method.
when final assy is done just make sure the gear backlash is correct.
if you cant find the lead paste for marking gear tooth contact patterns an alternative is to mix 30wt motor oil with powdered chalk from a chalkline. mix it very thick and it will work ok for checking tooth contact.
last lead paste I got was from the local chevrolet dealer, prussian blue works well but its very hard to clean off for another try at checking patterns.

 

[flabum]

Re: bearing replacement, shimming

There is a tool that you will need to postion the drive gear. It goes in through the top of the drive and you put the drive gear in position and measure the clearance. With a little math, you figure out how much shim you need. If you don't change anything on the driven gear, you don't need to check it "normally", but if you want to be thorough, then you will need another tool for it. The upper tool is part #91-60623 or Sierra#18-9855

http://ww2.sierramarine.com/catalog_pdf_8024/Sierra_8024-119.pdf

 

[ziggy]

Re: bearing replacement, shimming

Like I said, the correct method of torqueing the pinion nut depends ENTIRELY on the bearing design. one uses a rolling torque the other a straight torque.

its up to you to determine which design you have and use the correct method.

hum, ok, i aint got the new brgs yet.....i hope that i ordered exact replacement brgs. and spacers..

i guess my confussion is that it don't talk about anything other than stright torque. untill ya get to manaul #4. i use #2. in #4, it talks about if i do or don't use the small spacer as being the determining factor for weather or not i use rolling torque or straight. what i have exisiting i feel is the straight torque version. only because i have the small spacer is why i feel that way though...maybe i need to see what kinda new brgs i get. perhaps seeing the new will help me see the light.....i probably shoulda just used the ones i had.......i'm causeing myself troubles....

when final assy is done just make sure the gear backlash is correct.

you mean shiming @ .025"? that i plan to do...... along with useing the timeing marks on the 1:65 gears to be back in the same place on the gears as before... thanks for your helps folks......bondos idea is sounding better all the time.......someone else do it...... hope i don't end up takeing it to my dealer in a basket. he already warned me it's gonna cost me if i do that............

 

[rodbolt]

Re: bearing replacement, shimming

dont get scared, its not hard. if you have identifed the bearing designe,one spacer or two, then follow that procedure for torqueing. since this is your fisrt attept then after shimming carefully check the gear backlash and tooth contact pattern.
always remember loose lives.
your hunting for a backlash of about .006-.011 with an even tooth contact pattern.
dont mess with the driven gear height as your not messing with it. to get a rough idea of if the shimming is going to change and by how much simply stack the old and new bearing sets on a flat surface and check the height of the stack with a depth micrometer or calipers.

 

[achris]

Re: bearing replacement, shimming

It's a while since I ordered a new bearing set, but I think they come with the instruction for setting them up. The reason you're not seeing the rolling torque method of setting them (in the manuals you have) is because Merc didn't start using that method until after the manuals you have were printed.

Chris..........

 

[ziggy]

Re: bearing replacement, shimming

thanks guys for your help. ya got me thru that.....
well, i had 2 spacers and old gears. so it got torqued to 85 ft. lbs per service manaul #2.

the new brgs did come with instructions. for setting up the rolling torque. this is the method to use per the instructions when the drive gear has been replaced. it has a .0014" larger dia. where the brg.s ride on. so they get pressed on. and ya don't use the spacer. since i used my old gears, the instructions refered me to service manual #6 for seting up proper with straight torque. there is a torque value difference between #6 and #2. 6 i think says 70-80 ft. lbs. #2 says 85 ft. lbs. i went with 85.....

in process of shimming now. .037 wasn't enough, .040 is to much.... next try will be .038, which is what i took out.......it'll probably be .039 so i can practice taking it apart more though...... just wanted to let ya know what happened so far.... thanks...

 

[ziggy]

Re: bearing replacement, shimming

i 'think' i'm gettin happier by the moment. .038" shims was the ticket. same thickness as with the old brgs. on three teeth, got it after the third try. took it apart and put it together 4 times, last time with perfect seal on the retainer nut. third and forth time, .025" feeler fits nice and snug. .026'' won't go in on any teeth, and .024" goes in real easy on all three. check in two places, removed shim tool and checked two points again. same result. i'm satisfied i got .025". pressuer tested @ 15psi for as long as i could hold my finger over the hole, did turn drive shaft, no change. still held............turning drive shaft is a bit stiff like cold gear lub, nice and smooth, no feeling at all short of being stiff.........guess i'm moveing on unless someone don't think the results are what i'm lookin for.......

 

[achris]

Re: bearing replacement, shimming

STOP!! STOP!! YOU'VE DONE IT ALL WRONG!! DON'T DO IT THAT WAY....

Well done Ziggy... Sounds like you'll be teaching us before long...

Cheers,

Chris...............

 

[Don S]

Re: bearing replacement, shimming

So Chris, How's Russia this time of year?

 

[achris]

Re: bearing replacement, shimming

Just like Alaska at this time of the year.... c-c-c-c-cold....... I'm in Vladivostok for the night. Fly to Petropavlovsk-Kamchatsky tomorrow.... It's even colder there!!!

 

[Don S]

Re: bearing replacement, shimming

Now you know why I left Alaska. But, it's cold here to........ 42? and raining.

 

[achris]

Re: bearing replacement, shimming

It's fine, sunny and 20 degrees here.... about minus 5 where I'm headed. At home (Perth) it's going to be 100 tomorrow and 106 the next day... I miss the warm already. I thought you were disappointed to leave Alaska... Well there you go....

Chris...........