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MG MG Y Type - Slip Ring Repair

I have just repaired a very worn set of slip ring contacts, and wondered how others may have done this.

I used brass strip and brass screw heads to make new contact and soldered them to the remains of the original contact fingers.

And on a related issue, is the size of the wiring to the horn a little on the small size considering the current draw of the altette ?.

I have searched this BBS and the IMGYTR site for "slip ring", but no mention of repair methods, yet I'm sure I have read something somewhere - but where ?.

Thanks in anticipation,

Tony
A L SLATTERY

Tony

When soldering the slip ring 'fingers' - what solder did you use? Regular LEAD solder is way too hard and has too many abrasives in it. You MUST use SILVER solder only. Lead will score the brass rings out in no time flat. Silver solder is much more expensive and hard to get (as a jeweler for some though) than lead.

If you used LEAD - unsolder and resolder with SILVER.
Paul Barrow

Very good point Paul, I had not thought of that.

However, the solder has no contact with the rings, the contact point is the head of a small brass screw - so brass rubbing on brass. When this wears away, there will be a thin solder layer in contact with the ring, but it will take years and years with the current usage of my cars to get to the solder.

I used flux cored lead solder to keep the heat down - I didn't want to crack the Bakelite. What is the melting point of silver solder compared with lead solder ?.

The join of the soft brass finger to the original (spring brass) finger is also well away from contacting the rings. My aim it to make the replacement of the contact buttons a relatively easy process in the future.

Obviously, the only way to test my repair is use it, so time will tell I suppose - remind me to do a wear check in 1 year. I will take a photo later & post it here for clarity if anyone is interested.

I wonder what material formed the original contact buttons ?. It must have been quite soft to wear away so fast !. I don't recall having ever seen a slip ring that still had the original contact buttons, but these cars were already 40 years old when I saw my first slip ring internals.

I do have some silver solder & flux, so will use that from now on, so thank you for your advice and sharing knowledge.

Cheers

Tony
A L SLATTERY

Tony. You will have to cut out any area the has led solder before you try to silver solder. The lead reacts and eats the brass at the temperature needed for most silver solder. The temps start about 600 degrees. I don't think you want that temp around the bakelite. I think your brass screwheads should be fine. If they get any corrosion a turn or two of the wheel should cure that.

Butch
R Taras

Tony
Have a pic of a early slip ring contacts. I would imagine later contacts would be similar
Cheers Rob

R J Snell

Hi Butch, Thanks for that advice, I will make the next set using silver solder for the contact repair fingers/buttons, but use lead solder to join the new fingers to the existing fingers to avoid the heat issue.

Thanks Rob, I thought they would look something like that, but wonder what they were made from and how were they attached to the fingers. The small holes in the end of some fingers lead me to believe they were sort of riveted or pressed on ?.

I have never seen that early type of slip ring - very interesting !. Must see if Y1006 has an early or late type ?.

Cheers

Tony
A L SLATTERY

Tony
Have taken picks of both early and later slip ring contacts from the inside and appear pressed in. 1006 should have earlier type according to Le There be Y's. You are welcome to both early contacts and column if you want them
Cheers Rob

R J Snell

Other pic

R J Snell

Tony,
If you worry about current draw why not wire the altette through a relay,then current draw would be minimal.
John UMG624
JC Jebb

Good idea John. It could easily be tucked away near the slip ring on the inner guard. It was really more about the size of wire from the slip ring to the horn button in the original design - quite small compared to the wire to/from the horn itself !.

Yes please Rob, as I don't have a spare early type and the trafficators on Y1006 are playing up and I suspect the slip ring contacts.

I drove the YT yesterday and have lost the left flasher, so maybe another slip ring repair to do !.

Cheers

Tony
A L SLATTERY

I am in process of rebuilding my YA steering column and had the slip ring contacts built up with a bead of silver solder as recommended, replaced the Bakelite locating pin that had snapped with a brass stud threaded with a drop of Loctite into the Bakelite body and I am on the point of reassembly and note from the manual that the slip rings should be smeared with petroleum jelly. Now having done some reading I understand petroleum jelly, Vaselene, is an electrical insulator surely not ideal in this situation. Is there any wisdom on this subject?
Richard Verrill

Just a thought. I know that we are talking about contact fingers. But, to make new plastic pieces we should look at 3D printing.

Butch
R Taras

Quote;
Now having done some reading I understand petroleum jelly, Vaselene, is an electrical insulator surely not ideal in this situation. Is there any wisdom on this subject?
End Quote

Here is some Information.

http://www.w8ji.com/dielectric_grease_vs_conductive_grease.htm

Jim B.
JA Benjamin

Hi Jim,
The book is correct - use Vaseline.

You do not want grease that conducts electricity.

Imagine if you had a thin line of grease from one ring to the next - you would have all sorts of short circuit issues.

The tension on the fingers (& pressure on the rings) & the amps are enough to break through the Vaseline & pass the current.

As for 3D printing - that would be OK to replace the Bakelite, but not the spring brass fingers.

Just my two cents worth...

Tony
A L SLATTERY

Thanks Jim & Tony.

Ignorance is bliss or is it a little knowledge is dangerous? I should just follow the manual!!

But another thought, all parts are now nicely painted, the earth strap connection goes to the clamping clip that holds the cable cover on the steering column, this obviously needs to have good continuity needing removal of paint on the inside of the clip and a corresponding area on the column, would this be a place to use dielectric grease?

As for 3D printing I am dying to find a use and have a go.
Richard Verrill

Richard

I have just recently completed a 3D print to remake the ring for the trafficator controller. These will be available shortly through YZ Publications. They are not cheap as the cost of development from 3D scanning through prototype to finished product involved quite an up front investment, but the finished product will help someone who has a broken one as you are looking for hen's teeth if you break yours!

Paul
Paul R Barrow

This thread was discussed between 27/05/2016 and 19/07/2016

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