monty Posted July 28, 2015 Report Share Posted July 28, 2015 Just noticed a pool/large blob of oily grease under the wiper motor on the painted shelf next to the bulkhead. Appears to have leaked from the motor somehow. Any suggestions why & how to fix? How long before the rack seizes? Cheers. Quote Link to post Share on other sites
AlanT Posted July 28, 2015 Report Share Posted July 28, 2015 These motors run pretty hot. The grease has probably gone down the shaft of the big gear and out around the circlip. There are no oil or grease seals. Also the top plate is usually not very flat and makes no seal on the die-casting. When I build one up I run at 16V for about 1hour. Usually some grease will appear. I don't think the rack will seize. At least not because of this. Time how many sweeps you get in a minute. Off-load these do 45rpm. If you are doing say 30 sweeps it suggests the rack is tight or the wheel-boxes are rusty. Slow running like this will raise the motor temperature. Measure the current in the green 12V wire, it's about 2.5A off load on a new motor. If its gone up above 4A or so then it's another sign that things ain't running smoothly enough. Quote Link to post Share on other sites
monty Posted July 28, 2015 Author Report Share Posted July 28, 2015 These motors run pretty hot. The grease has probably gone down the shaft of the big gear and out around the circlip. There are no oil or grease seals. Also the top plate is usually not very flat and makes no seal on the die-casting. When I build one up I run at 16V for about 1hour. Usually some grease will appear. I don't think the rack will seize. At least not because of this. Time how many sweeps you get in a minute. Off-load these do 45rpm. If you are doing say 30 sweeps it suggests the rack is tight or the wheel-boxes are rusty. Slow running like this will raise the motor temperature. Measure the current in the green 12V wire, it's about 2.5A off load on a new motor. If its gone up above 4A or so then it's another sign that things ain't running smoothly enough. Many thanks Alan for this very useful info. Heat would explain the sudden appearance of grease, after the trip to Silverstone last weekend. Wipers on continually for at least 2 hours! Cheers. Quote Link to post Share on other sites
monty Posted July 28, 2015 Author Report Share Posted July 28, 2015 Many thanks Alan for this very useful info. Heat would explain the sudden appearance of grease, after the trip to Silverstone last weekend. Wipers on continually for at least 2 hours! Cheers. These motors run pretty hot. The grease has probably gone down the shaft of the big gear and out around the circlip. There are no oil or grease seals. Also the top plate is usually not very flat and makes no seal on the die-casting. When I build one up I run at 16V for about 1hour. Usually some grease will appear. I don't think the rack will seize. At least not because of this. Time how many sweeps you get in a minute. Off-load these do 45rpm. If you are doing say 30 sweeps it suggests the rack is tight or the wheel-boxes are rusty. Slow running like this will raise the motor temperature. Measure the current in the green 12V wire, it's about 2.5A off load on a new motor. If its gone up above 4A or so then it's another sign that things ain't running smoothly enough. Incidentally Alan, is it worth trying to replenish the grease? If so, do I just remove the top plate & try to force grease in? Thanks again. Quote Link to post Share on other sites
AlanT Posted July 28, 2015 Report Share Posted July 28, 2015 There is usually plenty of grease in there for lubrication purposes. These don't run fast and don't run all the time. Mainly the grease is useful to keep water out. If this is running freely and you are not making heavy use of it, like daily driving in February, I think you could leave it alone. The B90 exchange units come with about a desert spoon of grease under the big gear and about the same applied around the shaft of the armature. Of course after all this time the grease will have degraded a bit. It can go quite hard. So the real fix is to dismantle the whole thing and re-grease it. I do one here: http://www.tr-register.co.uk/forums/index.php?/topic/45402-rebuilding-a-wiper-motor/ The most important thing is to take of the end cap and check the carbon brushes. If these wear down it wrecks the commutator. Replacement carbon is easy to get and fit. I've lot loads. Should be like this: https://www.flickr.com/gp/90670218@N04/04K1q7 NOT LIKE THIS: https://flic.kr/p/mfjVT5 or you will end up with this: https://flic.kr/p/mfjVAG This may not look too bad but that copper is now paper thin and this is scrap really. Quote Link to post Share on other sites
AlanT Posted July 30, 2015 Report Share Posted July 30, 2015 Here is a Lucas B90 exchange unit, never used and properly stored since 1972: https://flic.kr/p/vK7stc and this is how much grease they put in it: https://flic.kr/p/wFgSsw I put more than this when I rebuild them. Especially on the crank-slider. In the cap I use this: https://flic.kr/p/iijTfC Water tends to get into the cap via the wire contact, unless it's one I have rebuilt that is. Quote Link to post Share on other sites
AlanT Posted August 12, 2015 Report Share Posted August 12, 2015 (edited) Here is one I just took as an exchange from another forumite: https://flic.kr/p/wYYS74 After all the years its been running the two grease blobs, that were under the gear wheel have done absolutely NOTHING: https://flic.kr/p/xeahAN Maybe you were supposed to move this grease somewhere more useful, anyway it's pointless greasing them like this. I fill the area under the wheel so as to prevent water getting in the spindle. It will come out a bit when I run them up hot at 16V. Edited August 12, 2015 by AlanT Quote Link to post Share on other sites
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