Disassembly of Minolta Maxxum 28-135mm f/4 Zoom Lens Photo Gallery by Pete Ganzel at pbase.com

Disassembly of Minolta Maxxum 28-135mm f/4 Zoom Lens

This beautifully made, all metal lens is probably the best example
of the craftsmanship that Minolta put into their products in the early 80s
The lens is carefully dust sealed and features solid lubrication blocks and a bronze
bearing for smooth operation. I won't go into the complex floating element zoom assembly,
suffice it to say that it is one most intricately machined components I've ever seen.
The internal focusing mechanism is fairly simple though, again, machined from solid metal.

Front Group Set Screw3439.jpg	Front Element Group 3440.jpg	Ground Spring 3436.jpg	Aperture Actuator Rod 3434.jpg	Focus Scale Ring Screw 3433.jpg
Focus Ring Tape 3432.jpg	Macro Switch Assembly 3447.jpg	Clean Zoom Rubber Oxidization 3443.jpg	Oxidized Rubber Before 3441.jpg	Oxidized Rubber After 3446.jpg
Solid Lubricant 3431.jpg	Zoom Ring Lock Screws 3429.jpg	Zoom Bearing Ring Tabs 3426.jpg	Zoom Bearing Ring 3422.jpg	Bent Zoom Bearing Ring Tab 3419.jpg
Straighten Bearing Ring Tab 3421.jpg	Prospect Park Tower 6085.jpg	Prospect Park Tower 6089.jpg	Prospect Park Tower 6092.jpg	gallery: Maxxum 28-135 f/4 Front Tube Excessive Play Repair
28-135-4-4.5 5.jpg	28-135-4-4.5 7.jpg	28-135-4-4.5 9.jpg	28-135-4-4.5 11.jpg	Macro Switch 2464.jpg
28-135-4-4.5 17.jpg	28-135-4-4.5 17.jpg	28-135-4-4.5 18.jpg

comment |

hai on		16-Sep-2023 21:23
Thanks so much for posting this. I needed the diagrams. Mine has fungus on the inner elements, I was able to dissemble the easier components the first time but was afraid to go deeper without the diagrams. hai

jasper		09-Feb-2021 16:56
Thanks for this great 'repair manual' it helped me restore my cheaply found 28-135mm. It was hard to find why mine didn't focus to infinity but eventually i noticed that the element under the front element was not screwed in all the way so i turned it furter on so it wouldn't turn any more and it worked!! ones again thnx!!

eyelevel		20-Jun-2016 10:21
I have got this lens and yesterday would not zoom at the top end it will zoom between 28 - 60mm approx. but will not go beyond that. Could this be a problem with the zoom ring? Thanking you very much in anticipation of your reply.

Jerry		18-Mar-2016 18:07
Lens works perfect except it will not zoom down to 28mm stops at 35mm it's great from 35-to 135mm. need an experts advice. Thanks, Jerry

Ralph Bullis		28-Mar-2009 17:21
When I zoom all the way out to 28mm the lens shifts to Manual Focus! A slight zoom in puts the lens back to autofocus. Would this be hard to correct?

John		06-Oct-2008 22:09
Fixed it. It was impossible to solder the contact pins back on. So in the interests of science I sacrificed a cheap nasty plastic 70-210 f4.5-5.6 lenses (worth about £10 and not used it in 4 years). Took off rubber grip and under rubber grip there is some black tape. Removed tape and attached under tape is the metal plate with contact slider pins on it. Trimmed base of new plate to size as the base that holds pins is a lot bigger, broke off remaining two contacts on old plate then soldered the whole set of contacts from cheap lens on top of where old contacts were. Adjusted the two inside contect pins carefully to make sure they ran on tracks. Then re-assembled lens. Jobs a goodun. 28-135 now focuses perfectly from 28-135. Focus is blisteringly quick on my 7D and doesn't hunt indoors in lower light at all. I recommend these sliders are checked over if anyone has one of these lenses where focus is slow or hunts. Thanks John

John		03-Oct-2008 15:06
Hi, Just picked up one of these lenses for £15. Used your guide to great effect and found out the zoom ring was broken (luckily between two screw holes and not a bit with a end stop attached) so after realising I couldn't straighten the broken bit I just left it out (zoom works great now). My next problem is focus. It works 100% fine between 28 and 80 or 90mm but above that it doesn't hunt then find focus it just hunts back and forth somewhere near focus point (same in my 7D and 700i). So I had a little look and saw all but one of the sliding contacts were flattened down so no contact was being made. I gently bent up the pins so they would make contact to the slider board and 3 just fell off. I was wondering if the pins should be always in contact with the sliders on the board above and is there anywhere I could source a replacement set of pins? Thanks for guide

John		03-Oct-2008 15:06
Hi, Just picked up one of these lenses for £15. Used your guide to great effect and found out the zoom ring was broken (luckily between two screw holes and not a bit with a end stop attached) so after realising I couldn't straighten the broken bit I just left it out (zoom works great now). My next problem is focus. It works 100% fine between 28 and 80 or 90mm but above that it doesn't hunt then find focus it just hunts back and forth somewhere near focus point (same in my 7D and 700i). So I had a little look and saw all but one of the sliding contacts were flattened down so no contact was being made. I gently bent up the pins so they would make contact to the slider board and 3 just fell off. I was wondering if the pins should be always in contact with the sliders on the board above and is there anywhere I could source a replacement set of pins? Thanks for guide

bob		08-Feb-2007 15:44
Thanks everything works great

robert soave		30-Jan-2007 12:38
thanks the problem is its doen so i have to figure whare to put it no . but i do have 1 of these lenses apart and 1 together so it took the other apart to find out what s the problem and reasembled no my macro is not working its all blurry but every things else is fine so i will just keep pluging away thanks for your help and a reply to sam on oily blaids do not take that apart remove the assybly and wash it with a lot of soap and hot water an put over a heat duct for a hour that works for me

Pete Ganzel		12-Jan-2007 05:27
Bob: If you make a mark across both rings while you cut the tape you can put them back together exactly in the same place upon reassembly. Pete

bob		10-Jan-2007 14:34
hell hope someone will help me . i just did this complete overhaul on this thing. but trouble with auto focus . i think it has to do with the placing of the tape. on the focus ring is there a system to putting this in the correct spot thanks Bob

Howard Yoon		03-Mar-2006 01:43
Pete, Through your disassembly photos, I was able to remove the fungus on the inner lens elements. I also just figured out the cause of the slow focus at 135 mm. Two of the sliding contacts were bent up, probably during the assembly. I took the retaining pin out of the aperture actuator and bent the sliding contacts back up. Now the lens works perfectly without "hunting" back-and-forth at 135 mm. Thanks Now I am tempted to get the 70-210 f/4.

Sam		27-Jan-2006 12:32
Hi there It looks like cleaning oily aperture blades would be a nightmare job. I've got no experience of doind this kind of thing. Would you recommend me to leave it to an expert? Cheers Sam

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