AlanT
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Posts posted by AlanT
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Motors usually fail because of worn out carbon-brushes.
Carbon-brushes are usually easy to fix as long as you can get inside the motor.
This is why I rebuild the wiper-motors. I can completely dismantle one in under 5 minutes.
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I do a lot of black-wrinkle on the wiper-motors. I use the VHT paint, I've tried Hycote and this is poor in comparison.
The wrinkle process is quite tricky to get consistent. It's very dependant on the thickness of the coats and the number of coats.
The thicker heavier coats make bigger more clumsy wrinkles. More thin dry coats make a very fine wrinkle.
Temperature is important also. Really tricky to do in the Winter. You tend to get the clumsy wrinkles. This stuff likes to run easily and this is worse in Winter also.
I test the coats with my finger and go again when they are have reached the "tacky" stage as they dry. I use four thinish coats.
Remember I am spaying vertical surfaces. A horizontal surface would be easier.
I wait a few days and then cook for 1 hour at 100 degC. The paint is much tougher and harder when you do this. The wiper-motors get quite hot when running. If I did not cook the paint, it would go soft when I tested them. And then I'd pick it up and leave finger-marks.
I'd say you can get a good result with this stuff but it takes a bit of practice to get control of it.
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You should study the Greasy Hands guides on overdrives.
https://vintagetriumphregister.org/maintain/TransRebuild/TranIntro.pdf
My bet is on the operating valve. The setting of these is critical. The method with a drill-bit though the operating lever worked when new maybe but is flaky when wear is present.
Do it with a dial-indicator or a depth-micrometer.
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May as well have my two penny-worth.
You have now tried a lot of solvents ranging from mild to aggressive.
There is almost no grease that or glue that won't dissolve in Thinners. Quite a lot of plastics do also.
So we must ask why you have failed.
I would guess that Biro is a mixture of a dye and a grease. The dye maybe particulate based because these are harder to remove and basically that's what you want! You have probably got rid of the grease but not the dye.
I'd also guess that Vinyl is partly porous so it's hard to get the dye to float out. Removing the grease won't have helped do this.
So oddly, I would start by adding a coat of light oil and letting this soak in. My mother had a beauty product that was a absolutely colourless oil. You are hoping to mobilise the dye and release it from the Vinyl.
After a day or so I'd remove as much oil as possible with paper-towel.
Then the magic trick. Talcum powder or baby-powder. This stuff absorbs grease and maybe with it the dye.
This worked on my wife's blouse the other day. With stain removing, failed attempts usually make later attempts less easy.
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Normally one BUT two is a very good idea.
The "proper" old ones work by switching, this is efficient and makes no waste heat.
"Modern" electronic ones use voltage regulators that just turn excess voltage into heat.
But they make them the same size as the old ones.
They are on the limit of overheating if both gauges are right over.
One per gauge is a better bet.
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Another job needed was to fit new rubber bushes into the mounting plate.
Luckily at this time there is a good supply of these at a low price:
These are proper rubber, unused and exactly right.
They are very difficult to get into the plate and often get cut in half. This spoils the job and is not necessary. But there are a few tricks to get them in.
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Well there is a lot of new wire in this motor.
One of the cases of "black-wire", overheated from being left stalled with power applied at some time.
Think I would run the wipers on test before I fitted the dashboard. Just in case tubes and wheelboxes need a tweak.
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Put a little downward curl into the last 6in or so.
Not easy to do unless you are used to making such adjustment to thin metal parts.
Very easy to end up with a kink instead.
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There are two chroming processes, TRI-VALENT and TETRA-VALENT.
This is from the original Chromium compound used to make the plating solution.
One of these is much more toxic than the other.
No surprise the toxic process looks better and lasts longer and is easier to control.
And no surprise the toxic process is getting phased out.
The new process tends to have a more blueish tint but this is operator dependant.
Google will tell you a lot more.
Nickel is a simpler and safer process and small parts can be DIY.
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Maybe something is stiff. This uses up extra torque and so you don't develop any extra speed.
What state of maintenance is the wire-rack, wheel-boxes and motor itself?
Can you measure how much current it takes?
Running light on the bench these take 2.5A on SLOW and 2A on FAST. With old grease, a rusty main shaft and a bent crank-arm they often take 5A to do the same thing. So a current measurement tells a lot. Do it in the 12V feed, GREEN wire but you probably can't see the colour!
Another possibility is that is that the insulation on the resistance-winding has failed. The winding has shorted turns and so in effect you are in SLOW mode all the time.
I rewind these all the time, about half of them have the cotton insulation rotted away. I'd only need you to send me the field-coil NOT the whole motor. Although they can be a bit tricky to get back together, they always go in the end.
These are heavy, just over the weight limit, shipping is expensive, £12.50 on Parcel-Force but Hermes is cheaper.
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For the record, a Moss dash-top is NOT the way to go.
I made it work OK but it took a bit of extra work.
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If TR shop dash-tops really are polystyrene, I think they maybe dissolved by AF178 also.
I'd run a test on a small area and possibly fall back to some less secure kind of adhesive like Gorrila.
The originals would have been expanded-polyurethane I believe.
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I used ThixoFix to secure wood veneer. It lasted about 45 years INDOORS. But it did come loose. It's about the same as ordinary EvoStick.
These all have the problem of grabbing, even though you are not exactly in the right place.
AF178 is a bit harder to handle but not much.
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I should have described to you the way I used this stuff to do really tricky stuff like Vinyl on the screen-frame.
I DIDN'T paint the whole thing with glue on both sides and then hope to drop it in the right place.
I did about 6 inches in the middle and positioning this was quite easy because the ends didn't stick.
Then do a a bit more at a time. Work out both sides from the middle.
Don't build up extra thickness of glue where you leave off.
Stagger the leaving off point on each side. So maybe 6in of glue on the metal bulkhead and only 4in on the dash-top.
I used a Moss dash-top and these are a kind of flexible rubber. If you have a stiffer type then you will need to do bigger areas but it will be easier to position than a more floppy one.
You could use some kind of plastic film, like the old fashioned Fablon, between the two parts so the glue does not touch. Then gradually withdraw this. Even waxy baking paper would be OK for this I think.
I'd put "alignment" dots with a marker of some kind every 2 inches and make sure to work to them.
The risk is you stretch out the dash-top as you go which then winds up too long.
All the upholstery type work and stuff like screen rubbers and boot seals has this stretching out problem.
Oh and do a DRY-FIT including the screen-frame to make sure it will all go. This will be much easier than trying to trim some off after you stuck it down and find the frame won't fit.
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The problem with having the switch wired OFF-FAST-SLOW is that you are asking the motor to start on the setting that gives minimum torque. It's like pulling away in top gear.
If the motor stalls, then the current will rise to 12A and if left like that for more than a short time, it will burn out.
My standard test asks that these will start at 6V on the bench. They all do this on SLOW but many struggle on FAST.
It will run FAST if you ONLY ground the red wire and run SLOW if you ground red AND brown.
SLOW is about 33rpm and FAST is about 45rpm. Depends on exact supply voltage.
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Just what I did.
By the way it's not hard to dismantle these, clean the contacts and providing the plastic is correct, you will get it working again.
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I recently modified a TR6 wiper switch to work correctly on a TR5 with the 75568 square-bodied motor.
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Put some wood or polystyrene in the bottom of the door.
Now if you let the glass slip, or drop the end of the regulator etc you won't put a dent into the door.
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If you make big quantities of rubber items you can do something like the original method.
But small quantities are done with a two-part catalytic rubber in simple moulds. This is just not a long-life method.
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You will get trouble with almost any repro rubber items. The rubber is just not made with the original process.
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If the battery keeps up OK then the gauge is wired backwards.
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Please note that these holes were NOT originally round. There is a notch to accomodate the feed-pipe for the washer-jet.
I can't tell from the photo how much enlargement there is around this hole.
Compare with the other side and you may be able to work this out.
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Klingerite and a bit of windscreen sealant.
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Possibly not the DC voltage but vehicles are full of high-voltage "spikes" arising from switching of wound and therefore inductive components.
These spikes are hard to suppress, they contain quite a lot of energy. A bit more than a few bypass capacitors is often required.
When I put new brushes in the heater fan on a modern Vauxhall I found it had dual LC filter-sections. You never see this on classic vehicle components because there was no need.
TR4a Wiper Angle and Parts
in TR4/4A Forum
Posted
If I understood correctly you have a worn out big-end bush in the crank-arm.
I just made a batch of these and have plenty of crank-arms available.
Anybody that changes from the original 75568 motor can sell it to me. I am always looking for these.
120 degrees is original but 110 works OK. Your passenger may moan about the view.