Bronze gear bushing clearance - Page 3 - Alfa Romeo Bulletin Board & Forums
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post #31 of 70 (permalink) Old 03-09-2015, 01:58 PM
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Best way to remove and install bronze bushings?

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Originally Posted by goats View Post
Given the hassle of removing/opening/sealing the trans, and the cost of the parts I would probably go for it to tighten down those clearances. As I said, the bushes I got from Centerline were right at 1.3740 and beautiful machined, true, etc. 30 bucks each. If you are off (small) by a thou (ie not enough clearance) you can run the hone through yourself no problem, just make sure you clean it good after you do so (with detergent followed by solvent).
Thanks Bob,

Appreciate the help. A few more questions for you:

1. How did you get the old bushings out without damaging the gear?
2. If you were to do it again, would you use the same method of removal (or a different one)?
3. How do you get the new bushings into the gears?
4. Did you heat the gear and cool the bushing prior to installation?
5. If so, how hot (300F?) and how cool (freezer for 24 hours)?
6. Did you need to use a press?

Thanks again,

Edward
'88 Quad - "Claudia"
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post #32 of 70 (permalink) Old 03-09-2015, 02:54 PM Thread Starter
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1. Pressed em out with a hydraulic press
2. DO the same way
3. The new ones from Centerline pretty much dropped in, used locktite green and the hydraulic press again -- was easy to press em in
4 and 5 -- didn't need to


All in all it was pretty straightforward --

74 GTV with 10548's and Ingram pump
71 Spider 1750 BOMBER ; 1995 LS 78K tight fast car
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post #33 of 70 (permalink) Old 03-09-2015, 03:11 PM
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Quote:
Originally Posted by goats View Post
1. Pressed em out with a hydraulic press
2. DO the same way
3. The new ones from Centerline pretty much dropped in, used locktite green and the hydraulic press again -- was easy to press em in
4 and 5 -- didn't need to

All in all it was pretty straightforward --
Bob,

OK. That sounds great. I've got access to a beefy hydraulic press at work that I just adore.

Really enjoyed your thread and photos. Very helpful.

Many thanks,

Edward
'88 Quad - "Claudia"
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post #34 of 70 (permalink) Old 05-19-2015, 01:52 PM
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struggles and woes with bushing replacement

Even though the ID's of my old gear bushings were only about 0.005" to 0.009" over the related shaft IDs, they had noticeable slop/wobble so I decided to replace them and get them closer to 0.002" over.

The old bronze bushings came out easily with a 36.2mm diameter bronze rod and the press at work.

Got some new bronze bushings (the kind with the dimples and a seam) from a European supplier.

In order to equally center the new bushings in the gear bores when I pressed them in, I used a small "stop" plug (about 30mm tall) that I fashioned out of some 32mm rod stock. When my 36.2mm diameter bronze rod pressed the bush into the gear bore, it was stopped by the 30mm plug, resulting in the new bushing being about 1.5mm from either gear bore edge.

All good so far except the IDs of the new bushings were about 1.359" to 1.361", and I needed to get them opened up to the 1.3735" and 1.3765" range.

A local precision grind shop was able to hone, broach, or lap the bushes out to a "slip fit" on the shaft ($50 each). When I got them back I measured the bushing IDs and they were between 0.0011" and 0.0014" over the respective shaft ODs. They slipped on, spun freely, and had absolutely no wobble or slop. Looking good I thought, until I pressed on the dog gears. Lordy, why didn't I pay more attention to goats' post #5 in this thread? My perfect fit gears no longer fit onto the shaft!

So back I go to the precision grind shop. I explained how the dog gears had compressed the inner bores at one end, and asked if they could clean up the taper. They said no problem and another $150 later my gears slid on the shaft again and they were still between 0.001" and 0.002" over the shaft ODs. I thought I was in business, but when I rotated the gears on the shaft, I noticed just the slightest bit of wobble. Sure enough all 3 bores seemed to have been cut at a slight angle. First gear was actually 0.017" off from side to side.

Back to square one. Remove synchro pieces (OMG I hate those big snap rings!). Remove dog gears with press. Remove poorly honed bushes with press. Wait for more bushings from Europe. Press new bushings into the bores.

Even though the grind shop hadn't reported a problem with the other bushings moving in the bore as they worked them, I decided to use some green Loctite 620 on this set.

I have now pressed the dogs back onto the gears, and I am ready to have the bushings opened up again (as they all have IDs around 1.359"), but I don't want to go back to the same precision grind shop.

How can I get these things honed, lapped or broached out about 0.015", with a finished diameter accurate to within +/- 0.001", and perfectly centered in, and perpendicular to, the gear?

Is a bushing ID that is only 0.002" over the associated shaft OD correct?

And I am a little confused about "end play" vs. "axial play". I have several different Alfa Shop Manuals. Most of the 105 manuals refer to the "End play" of the gears (which I took to mean the lateral movement of the gear on the shaft), but my 1985-1989 Spider Shop Manual only refers to the "Axial play" of the gears.

In addition, the "axial play" tolerances in my S3 Manual are slightly different from the "end play" specs in the 105 manuals. For example, the 1st gear end play in the 105 manuals is specified to be less than 0.009" (or less than 0.0095") but the 1st gear axial play in my S3 Manual is called out to be between 0.008" to 0.012".

Any advice?

How to open up the bore IDs, and how much of a bigger diameter than the shaft ODs should they be?

Edward
'88 Quad - "Claudia"
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post #35 of 70 (permalink) Old 12-24-2015, 09:07 AM
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Goats,I'm ready to go through my mechanical clutch 5-speed,so I have questions.How's the transmission doing after several months? When/did you change oil after new rebuild,and did you find anything interesting? I have nos dimple type bushings.After following your adventure,I'm thinking of selling these(I have five) and getting spiral/one piece bushes,..yes? Can you describe or post picture of the type of hone you have and how you used it,ie.,hand,drill,drill press,lathe,? Any leaks,what sealant did you use? Any afterthoughts and suggestions. Thanks for anything,Phil D
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post #36 of 70 (permalink) Old 12-24-2015, 09:42 AM Thread Starter
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Hi Phil

Not much to say really other than what I posted last year. The hardest part of the job should have been the easiest part-- trueing up and matching diameters on those bushings.

I think the one piece no seam are the way to go. At least for me- they basically fit perfect out of the box. If u use the original you will need to expand it in place .

My trans is like butter. Couldn't be happier. I ran redline 75-90 NS per Richards advice, drained it after a couple hundred miles, was perfectly clean. So I reused it after passing it thru a lab filter ; absolutely zero on the filter paper. Filled to three pints and it's fantastic.

Keys to the job -- 100 percent absolute cleanliness. Every part in the solvent tank then fresh brake cleaner. Use a towel on ur bench. You can not be too clean. Hone is a small engine cylinder home from Sears in a battery powered hand drill. If you hone, clean clean and clean again. Loctite green for the bushings and anaerobic sealant and accelerator for the alum casings. Torque to spec. Be meticulous and you will enjoy the results! Richard did I miss anything?
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post #37 of 70 (permalink) Old 01-30-2016, 07:22 PM
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Well,I guess I waited too long.The spiral bushings are no longer available.Classicalfa and Centerline both had these,but for whatever reason,went to the old style dimple/split bush.So now I really need to know what's involved in expanding the bushings before machining/honing?Regards,Phil D
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post #38 of 70 (permalink) Old 01-30-2016, 10:03 PM Thread Starter
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phil -- I myself would not worry too much about this. Get the new ones and lets see how they fit. If its loosey goosey then suggest you ask Richard J how to do this--he is prob the most experienced source there is. If its pretty tight then me myself-- wouldn't worry about it. Id locktite green in place, hone em out and be done with it.

PS I am going to rebuild another trans for my 'dream spider'(yeah right) here in the next 8-10 months -- I think I learned most of my lessons already......but am also certain there are more to come!

74 GTV with 10548's and Ingram pump
71 Spider 1750 BOMBER ; 1995 LS 78K tight fast car
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post #39 of 70 (permalink) Old 01-30-2016, 11:33 PM
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Hi Phil,

I've only used the dimpled style split bushings before, and I can attest that they are too tight to drop or slide easily into the gear bores. I've always used a press to shove them into place.

I wash the gears and bushings real well with Acetone and let them dry, then use Loctite 620 when assembling them.

The tricky part for me was finding a competent machinist to hone the bushes out a mere 0.015" while maintaining concentricity to the gear pitch and perpendicularity to the gear end faces so that they ended up only 0.002" over the OD of the shaft. I've never watched him, but I think my guy chucks up the gears in the lathe by putting some small rods in the gear teeth, and then verifies zero runout prior to cutting.

And it's important that the dog gears are fitted prior to the honing operation, because surprising as it may seem, the pressure from the installed dog gear noticeably compresses the gear ID at that end of the bore.
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Edward
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post #40 of 70 (permalink) Old 06-08-2016, 08:53 AM
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Great thread. Looks like my trans rebuild may take longer than I thought...

72 GTV; 66 Fairlane GT convt, 428, 4 sp; 68 GTO Convt, owner built 455 and TH400; 71 Javelin road race project, owner built 401, T10
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post #41 of 70 (permalink) Old 07-19-2016, 07:20 PM
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Soft Jaws

Worked out well for me getting two sets of soft jaws from ebay, cutting them to fit for each gear. Very repeatable results with some fiddling on my old lathe. We should have the gearbox back in later this week or next. Hopefully this set turns out to be the best yet.

I have photos but cannot post them yet. Not sure what happened to my old account. Had to start a new one.
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post #42 of 70 (permalink) Old 07-19-2016, 11:30 PM
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Quote:
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Worked out well for me getting two sets of soft jaws from ebay, cutting them to fit for each gear. Very repeatable results with some fiddling on my old lathe. We should have the gearbox back in later this week or next. Hopefully this set turns out to be the best yet.

I have photos but cannot post them yet. Not sure what happened to my old account. Had to start a new one.
If you e mail the pictures to me, I'll post them. Very curious to see how you did this.

I'll pm you my e mail address.

Scott

72 GTV; 66 Fairlane GT convt, 428, 4 sp; 68 GTO Convt, owner built 455 and TH400; 71 Javelin road race project, owner built 401, T10
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post #43 of 70 (permalink) Old 07-20-2016, 12:38 AM Thread Starter
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Great to hear this, Erik is a fine (precision) machinist and an excellent trustworthy Alfa (and others!) wrench!! if he says its good -- it's good! He taught me 5 speed box rebuild for certain!
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post #44 of 70 (permalink) Old 07-20-2016, 01:53 AM
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Erik -

Here are your pics -









Norseman50 likes this.

72 GTV; 66 Fairlane GT convt, 428, 4 sp; 68 GTO Convt, owner built 455 and TH400; 71 Javelin road race project, owner built 401, T10
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post #45 of 70 (permalink) Old 07-20-2016, 07:50 AM Thread Starter
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That's a pretty sight right there! As long as the lathe and soft jaws are properly set up (which in Eriks case Im sure it is) then this will be a fine setup to get these troublesome bushings properly sized

74 GTV with 10548's and Ingram pump
71 Spider 1750 BOMBER ; 1995 LS 78K tight fast car
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