TA 21 Windscreen Wipers

For all TA 21, TB 21, TC 21 and TC 21/100 cars
Cavendish51
Posts: 14
Joined: Wed Aug 28, 2013 1:14 pm
Name: J. Simon Rigge

TA 21 Windscreen Wipers

Postby Cavendish51 » Tue Sep 01, 2015 10:53 am

I am getting to know my car again after 20 years off the road. Sometimes the wipers become lazy or stop entirely on the upward stroke. This can be quite alarming on a busy road. A touch on the accelerator can often give enough extra charge to nudge them back into action, but on occasion even this doesn't work. If the rain comes down more heavily, they can revert to normal. Once they're going properly, they keep going. The problem seems to occur when the car has been out of use for a week or two. After the last episode a week ago, they've been running normally, which is a huge relief, but the fear remains that I might once again be blindfolded! Has anyone else encountered this problem? Does anyone know what the cause or cure might be?

RichardWallach
Posts: 350
Joined: Mon May 21, 2012 10:14 am
Name: Richard Wallach
Location: Melbourne, Australia

Re: TA 21 Windscreen Wipers

Postby RichardWallach » Wed Sep 02, 2015 10:12 am

After 60 plus years the solution is simple, namely an overhaul. In essence it appears that the motor does not have the torque to operate the mechanism. You can quite easily pull the whole thing down yourself in a weekend and rejuvinate the system, all for near zero cost. I have made the assumption that you have a good wiring harness with little voltage drop.

The first part involves removing the rack and motor assembly. By removing the top of the dashboard (two screws) will expose the rack. Remove the wiper arms and undo the screws. The rack will become loose. Next remove the motor and then its top cover. I imagine that what you will see is semi solid old grease. Study carefully then remove the rack from the end. The rack can then be removed from inside the car. Pull off the wheel box covers and inspect the gears. You can replace them 180 degrees if the teeth are worn down. This will then give you a new set of teeth. Undo the cable outers and clean the rack cable with petrol/turps. Clean out the wiper arm boxes. When you reassemble I mixed oil and grease together so that the mixture provided less friction.
If you are happy to pull the cover off the wiper motor that will help. Remove the brushes (check for serviceability) Remove and clean the armature. Clean the housing and end gear wheel drive and when assembling re oil and smear some grease on the eccentric of the gear wheel. If the motor is really beyond repair the you will probably find another on ebay.

If all is generally OK reassemble the motor. The top cover has a bearing for the armature, make sure that it is cleaned and a little oil added. Oil sparingly near the armature. When the motor is back together you may find a little screw and nut on the outside of the case near the terminals. Loosen off but do not tighten down too much until the whole system is up and running. If it is too tight it will cause drag on the armature.

Reassemble as per disassembly, noting that it if not done otherwise,it is best to replace the two rubber seals that the wiper arm project through. If desperate just use ordinary grommets.

The motor is not polarity sensitive so will work with both positive or negative grounding.

With the above done all should be well.

Good luck.

Richard
Merlbourne

Cavendish51
Posts: 14
Joined: Wed Aug 28, 2013 1:14 pm
Name: J. Simon Rigge

Re: TA 21 Windscreen Wipers

Postby Cavendish51 » Sat Oct 17, 2015 10:38 am

Many thanks for those instructions, Richard. Since I wrote, my car has been back up in Coventry for other teething problems to be attended to. I am due to get it back next week. If my wiper laziness persists, I'll know what to do. Simon.


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