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MG MGB Technical - Another wiper issue
|My 1974 mgb roadster and the wipers barely move or not at all. When I remove the wiper arms/ blades the wheel houses work fine. Motor/gearbox look fairly new. Previous owner passed away so no way to tell. I cleaned the blades and windshield and sprayed water,but not much help. Any ideas? Did not find in archives exact situation. Thanks, George|
|It's possible that the grease in the wiper rack/tubes has dried out and is putting a lot more strain on the motor.|
|Dave O'Neill 2|
|It is also possible that the spindles are binding. If it is the spindles, shooting some penetrating oil in them can help. If it does help, follow it with some kind of lube. If that doesn't work, then it is likely what Dave said.|
|C R Huff|
|Yep, Time for that fun project of pulling the wiper, cable and wheel houses and giving them all a cleaning. It does not take much to gum up the system.|
|While removing the wiper motor I found the middle wheelhouse was funnier and had one spot it tightened up. I kept spraying penetrating spray foam in from the outside. Finally freed it up like the other 2. I think that was the problem, but I am cleaning the motor, gearbox, and the inner drive cable. Then I will relube everything and I think it will work great. Hopefully I will get everything back together tomorrow and I will let you know how it works. Thanks, George|
|Could also be electrical. If there is excessive resistance in the circuit from bad connections the motor will turn slower under load, which draws more current, which drops more voltage across the poor connection and leaves less for the motor, which runs slower than it should. As a 74 the current path is from the solenoid through the ignition switch, fusebox, and several bullet connections so plenty of scope.
It's not easy to get to the motor terminals on Mk2 and later to check voltage, but the motor should draw a current of 2.7 to 3.4 amps. Three-blade systems will run slower than two, in fact with 50% increase in the mechanical loading it's almost a surprise that they do much at all.
This thread was discussed between 14/10/2017 and 16/10/2017
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