Angle Drive Diagnostics

[TTait]

My speedo just stopped working. The cable was tight into the back of the speedo.

I have the single long cable setup, no service counter.

I unhooked the cable from the angle drive and spun it with a drill, the speedo worked.

I took off the wheel and observed that the dust cap was not spinning (yay - cheap fix!)

I removed the dust cap and it had no obvious wear.

I then used a drill to spin the input spindle on the angle drive, and the speedo worked - I assumed the dust cap was just loose.

I cleaned and inspected the dust cap and reinstalled it with a bit of silicon adhesive around the perimeter and let it set up. I spun the wheel and I could hear ticking, no speedo movement. Took the wheel off again and the spindle was now snapping inside the dust cap, but the dust cap was now spinning with the wheel.

I removed the dust cap tried to turn the spindle by hand - no dice, either way - way too tight to turn by hand.

I unhooked the speedo cable - it turns by hand with about 50% of the possible effort my fingers could exert.

I then tried to spin the angle drive, with the cable not attached I could turn it but it took about 80% of the force my fingers could exert, and the output turns.

What do we think - replace the angle drive, the dust cap, or the speedo cable?

I'm assuming the angle drive... Advice appreciated - I'd like to get this fixed quickly.

Tom

[stevedmc]

Are you sure the metal shaft is fully seated in the dust cap? The rod on my DMCH unit was actually too short to go all the way in the dust cap. It basically wasn't making a connection and couldn't spin because of this.

I replaced my DMCH angle drive with one from Hervey (his has a longer shaft that goes into the dust cap) and things have been great ever since then.

[Jonathan]

This sounds about like my speedo this weekend. Mine died yesterday. When I got to our club event, a friend and I took off the wheel for a look. The angle drive cable was very difficult to turn with your fingers but fairly easy to turn with some pliers. No signs of damage or slippage on the dust cap. With the lower speedo cable disconnected from the angle drive, the angle drive turned somewhat easy and the lower cable spun fairly easy too (and you could see the speedo needle move).

The problem seems to be similar to yours when you plug the two together. Like you said, it takes most of your finger strength to turn it. So time was running out and we tried our best to secure the cable from bouncing around (I don't have the bracket so we zip tied to the brake line). The speedo worked for about 50 feet.

Fast forward to today when I was back home with my tools and garage. I lubes the angle drive after taking things apart and the angle drive alone REALLY spun easy now. Ok so we're getting somewhere. I connect things again and the system doesn't spin quite as easy as when apart. I go for about a 15 mile drive and it was working but died on the 14th mile.

So a couple ideas. Lube the lower speedo cable somehow or also lube the lambda counter (I need to reset it anyway after doing my O2 sensor). Not sure what else to do if lubing the cable portion doesn't work??

[TTait]

I no longer have the upper and lower speedo cables with the service counter in the middle, I have a long 1 piece cable that goes from the angle drive to the speedo directly.

I'll lube that a bit, but I think the drive is dying...

Steve, I'm pretty sure the spindle is into the cup far enough, but I may try Mr. Hervey's angle drive too - does he sell dust caps?

Can the angle drive be over lubed?

[TTait]

also - John seems very proud that his angle drives have a replaceable flex shaft on them - why would the flex shaft go bad - I thought it was always the gearing inside?

[WelmoedJ]

Sometimes the flex shaft of the AD eats the square centre of the dust cap.

Happened to mine.
A new dust cap made the speedo works as intended.

A stuck or not smooth turning flax shaft will also round the square in the center of the dust cap.
Happened to mine too.

[content22207]

Despite what some British owners say, there are several problems with angle drive gears:

1) Being helical, only the center of the gear teeth actually intermesh with each other. A small amount of wear in the axle gear's brass bushing will allow it to fall away from the speedometer gear and no longer intermesh.
2) Gear teeth are not deep to begin with -- perhaps 1/32"
3) The gear teeth turn into each other, which naturally leads to binding (both gears are angle cut). You can feel the difference turning a brand new angle drive in your hand -- turning it backwards (clockwise) is easier and freer than turning it in the normal direction of wheel rotation

Bill Robertson
#5939

[stevedmc]

I no longer have the upper and lower speedo cables with the service counter in the middle, I have a long 1 piece cable that goes from the angle drive to the speedo directly.

I'll lube that a bit, but I think the drive is dying...

Steve, I'm pretty sure the spindle is into the cup far enough, but I may try Mr. Hervey's angle drive too - does he sell dust caps?

Can the angle drive be over lubed?

Hervey's angle drive is sealed and you cannot lube it. I don't believe he sells dust caps. My advice would be to order a dust cap from DMCMW (I love those guys) and an angle drive from Hervey.

If your old angle drive is from DMCH please put it side by side with your Hervey unit before installation. I really want to know if all of the Houston units have shorter shafts than Herveys or if I might have been sent a defective DMCH part.

[TTait]

I'd be willing to give John's a try, but I need it fast and I couldn't get him on the phone to confirm he could ship today, so I have a drive and dustcap coming up from DMCCA overnight.

I need to get the car back on the road as we are planning on having lunch with the original owner friday. He hasn't seen the car in 18 years.

[content22207]

Keep a laminated RPM xRef (formatted for easy reading at a glance, sized to fit over the speedo) taped to your glovebox lid with double sided tape. If your angle drive ever breaks, you don't even need to stop the car -- just reach over, pop the glovebox, stick the chart to your instrument cluster lens, and keep on driving.
2780

I've done it many times myself.

Bill Robertson
#5939

[John U]

or a GPS.....

[David T]

You should keep a laminated copy of the RPM/MPH chart in the binnacle. It is very close to accurate so you can still monitor your speed if the speedometer should die while you are driving. You can also use a GPS but there is a delay and it is not always accurate. Make sure you get the right chart, there are two, one for the auto and one for the 5-speed. The angle drive should be lubricated every year or 5,000 miles when you do your service.
David Teitelbaum

[Canon20DFan]

Good idea!

Keep a laminated RPM xRef (formatted for easy reading at a glance, sized to fit over the speedo) taped to your glovebox lid with double sided tape. If your angle drive ever breaks, you don't even need to stop the car -- just reach over, pop the glovebox, stick the chart to your instrument cluster lens, and keep on driving.
2780

I've done it many times myself.

Bill Robertson
#5939

[John U]

My needle bounces at low speed. I've lubed the angle drive and cleaned and lubed the lower cable and replaced the dustcap. Is this something I will just have to live with, or could there be and issue with the upper cable or the gearbox for the lambda counter?

[content22207]

or a GPS.....

I don't even have a cell phone -- do you really think I'd have GPS?

If maps were good enough for Vespucci, they're good enough for me.

Bill Robertson
#5939

[jmettee]

My needle bounces at low speed. I've lubed the angle drive and cleaned and lubed the lower cable and replaced the dustcap. Is this something I will just have to live with, or could there be and issue with the upper cable or the gearbox for the lambda counter?

Mine bounced below 35 for the first 3 years I had it. Change the lower cable from the long (early) style to the shorter (late) style & it only bounced below 25. Lubed the upper cable & not much of a change.

Angle drive failed back in May & I replaced it with a DMCH unit....speedo is smooth at all speeds now. I can't say your angle drive is about to fail....mine lasted about 10K miles doing the same thing until all of a sudden it stopped. No telling how the DMC unit will last....I see all kinds of mixed results & experiences.

[content22207]

Both Houston and Hervey offer 12 month warranties on their angle drives. Think of it like speedometer insurance -- $5 per month for a guaranteed functional speedometer.

Bill Robertson
#5939

[DMC5180]

Because it's not a matter IF, but rather when it fails. I keep a Spare NEW angle drive unit in the car. When that one eventually gets installed. I will replace it with another Stand By unit. I do the same with the Silverstar headlight bulbs I use in our daily driver cars. Or, the Special Deck belt on my lawn mower which usually fails once a season on SUNDAY with the dealer closed.

[John U]

haven't really looked into it yet....is it a pain to replace the angle drive?

[content22207]

You need a 1 1/4" open end wrench, which will likely end up being a single purpose tool in your collection.

I've never had any problem loosening the retaining nut with the assistance of a floor jack. Just remember that the threads are facing away from you -- righty loosey from that perspective. Turn the steering wheel to the left for access.

Bill Robertson
#5939

[jmettee]

You need a 1 1/4" open end wrench, which will likely end up being a single purpose tool in your collection.
Bill Robertson
#5939

That wrench works well for manual transmission cable adjustment nuts on the end of the tranny too :)

[Jonathan]

....is it a pain to replace the angle drive?

Hey John,

Call me or shoot me an email if you want me to walk you through this. It's really not that difficult. I've worked on my speedo components a few times and can give you a couple hints at how to diagnose or take everything apart.

Leave a message if I'm not home... might be down the street at the beach ;) Man oh man is this weather nice!

[TTait]

The parts came in today. (Sorry Steve, didn't buy the Hervey ones to measure.) I do note that if you don't tighten the rear mounting nut all the way the flex shaft will be shorter though.

Turning off the rear nut was a little awkward, but getting that darned little c-clip out was a pain in the butt - impossible to see. I finally had to give up and let the wife do it - took her 15 minutes.

Without the c-clip hiccup the whole job can be easily done in 30 minutes.

[John U]

Thanks Jonathan,
This will probably end up being a winter project for me....I will call you for help then....I'm sure you won't be at the beach :rofl:

[David T]

If the needle bounces pull the inner speedometer cables out and lay them on a clean piece of newspaper. They should lay flat in a nice large circle with no bends or kinks. The ends should not be frayed or damaged. If they are OK, lube them up with speedometer cable lubricant and reassemble, If they do not lay nice they should be replaced. As for the chart, I just leave it laying in the binnacle and if I need it, it is right there, I just stand it up.
David Teitelbaum

BTW Great minds think alike.

[TTait]

Depressing, but it speaks volumes when someone like David T just keeps an RPM sheet within reach always ready to go...

I had a lot of crappy cars back in the days of speedometer cables, and I never ever had a problem with the speedo on any of them. It shouldn't be rocket science to have a system that works at least as well as a Chevy Monza. or an Olds Delta 88, both of which were nearly 10 years older designs.

How long have Hervey's units been on the road? Anyone had one of those fail yet? (yes - I'm not assuming my new unit with 5 miles on it will fail soon too).

BTW - when removing the speedo cable I would tend to immediately mark it so that It was clear which end was which, I think it matters which way it goes in - right?

[David T]

I carry a lot of things in my car. They are not always for me. What I mean is that when I travel with other Deloreans I have some of the more common things that someone might need to keep going. I still have the original angle drive and have never had a problem with it but since it does seem to have a high failure rate it only makes sense to have a small piece of paper handy! I prefer to be prepared so not only do I carry *some* things with me I do a lot of preventative maintenance. "Back in the day" some venders used to print the chart on the back of their business cards.
David Teitelbaum

[TTait]

Helpful not just on line, but in the real world too.

In fairness the Angle drive that failed on me was 5 years old and had 20k miles on it - but I did lube it every 3k miles.

[content22207]

This is the speedo xRef I lived off of for many years (back in the days when replacement angle drives cost several hundreds of dollars):
2858
I formatted it to be easily readable at a glance. Taping it to the instrument cluster lens allows light to shine through it, making it readable at night.

Bill Robertson
#5939

[David T]

My theory on why angle drives fail is simple. I had one car that ate angle drives. I took the binnacle apart and inside one of the plastic posts had broken off. It still had a metal clip on it and got itself jammed in the speedometer mechanism because of the magnet. That made it hard to turn putting undue strain on the cables, angle drive and dust cover. If you have a car that "eats" angle drives or other parts I say you should open the binnacle and see what is going on inside.
David Teitelbaum

[content22207]

Autopsy a dead angle drive and you will likely find:
1) Vertical play in the axle gear
2) Convex wear in the output gear (put a straight edge across it)
The combined effect is gear teeth that do not intermesh anymore, rendering the unit useless.

Bill Robertson
#5939

[David T]

I agree the angle drives that fail are worn out to the point the parts do not line up anymore and properly mesh. My theory of excessive strain because of the jammed up speedometer head will cause the angle drive to work harder and wear out faster. Why do some angle drives seem to work forever and some do not last at all? They were all originally made the same. Something on ta particular car is causing them to wear prematurely. I do not believe it is a problem with the angle drive, it is just failing because of something else that is wrong. Over-engineering the angle drive is just putting a stronger Band-Aid on the problem. Autopsy the speedometer head the next time you wear out an angle drive.
David Teitelbaum

[outatym2001]

The parts came in today. (Sorry Steve, didn't buy the Hervey ones to measure.) I do note that if you don't tighten the rear mounting nut all the way the flex shaft will be shorter though.

Turning off the rear nut was a little awkward, but getting that darned little c-clip out was a pain in the butt - impossible to see. I finally had to give up and let the wife do it - took her 15 minutes.

Without the c-clip hiccup the whole job can be easily done in 30 minutes.

Here are pictures of the c-clip that TTait mentions above. I posted these pictures to the old dmctalk.com forum.
The C-Clip is actually a Retainer Wire as shown in the pictures. It’s a thin wire bent into a perfect circle.

[outatym2001]

Resurrecting an old thread about the Angle Drive, Dust Shield and the Lower Cable.
My speedometer and odometer quit working again (for like the third time in 22 years) and I bought online the replacement kit K106130 $89.99.
Some day you too are going to have your Angle Drive fail.
This five year old video on YouTube is a helpful step by step reminder on the procedure to replace the Angle Drive that I will perform again.
YouTube channel AutoFun with the video title below.
DeLorean Angle Drive Install & Lower Speedo Cable replacement (DMC-12 1981-1983)
https://www.youtube.com/watch?v=kb2NxCrK7Vg&t=5s