Seized Speedometer Drive Unit

Hey guys, one of the problems that I had with the XJ that I recently purchased, '81 XJ550H Maxim, was the non-functioning speedometer/odometer. I'm writing this topic so others who have a similar problem try what I did first before buying replacement parts that aren't really needed.

I took off the speedometer cable inspected/lubed it. It was fair. The ends looked slightly worn but no where near failure.

Ruled out the cable.

Next I tested to see if the cluster contained the malfunction by hooking up the speedometer cable into the cluster housing and spinning the other end of the cable with an electric drill. The speedometer registered a speed of 57 mph and added .1 miles onto my odometer.

Ruled out the cluster.

I lifted the bike up with a car jack and 2 jack stands (don't recommend, very unstable) and spun the front tire while looking into the input hole on the speedometer drive unit. The output hole didn't budge. The front wheel was removed and the drive unit was taken off.



I couldn't move the wheel input gear with my fingers nor any pliers. The darn gears were seized. Upon further inspection I concluded that the unit seized from grime that the grease picked up over time.

The first thing I did was remove the locking ring and a small thin washer that was underneath it. For this I used a dentists pick to pry it out-words and a lock-pick to 'unwrap' the ring. Worked well since it wasn't difficult to take off nor did the ring bend as a result.



Here's a picture of the unit with the ring and first washer off. You can see two slots on the input gear (more about that later) and some of the grime inside the unit. The outer housing was already wiped down... couldn't help it.



Since grime was the main suspect on why the thing seized I started to relieve the unit of as much of the debris as I could. Because the debris was held together in the grease, I broke down the grease using a bath of Dawn, and Simple Green.



I would alternate soaking the unit in the grease removal solution and boiling it with water.



When I got the majority of the crud out I felt it was time to break the gears free. Now I knew I was going to need to put a lot of force on the unit because I couldn't make it budge in either direction using pliers. Improvising I decided to use the following things:
Large Table Vise (to hold the unit)
Needle-type Vise-grips (to hold/rotate the gear)
Screwdriver (to amplify my favorite force, torque)
and some Polish persuasion



After utilizing a generous amount of torque the gears turned. Even so, they still were difficult to rotate by hand. Had to still use pliers but at least they moved! I continued to bath the unit in degreasing solution and boiling water 2 more times whilst moving the input gear. This little plastic piece fell out of the unit... have no idea what the heck the thing was doing there. (Later in the disassembly from what I could tell there was no place for it to be in there.)



After that the gears moved very easily, no pliers were necessary. I knew that in order to clean and lube the unit properly the input gear needed to be taken out. Because I didn't have the proper tools to pull out the gear I also improvised on this one, and bear with me this technique is a bit out there but it worked. I held the outer housing with two fingers and with the remaining three fingers and the palm of my hand I held the unit flat on top a small piece of 2 x 4.



Using Newton's 3rd law of motion I slammed the two against the floor 4 times (very hard, wood side down). On the fourth the input gear popped out along with another (this time slighter larger washer). The unit then was completely inspected and cleaned. To my delight the gears weren't that worn! Here are the pieces laid out in order of placement just waiting to be lubed with some good white lithium grease.



The larger washer goes in first, next the input gear, then the smaller washer, all topped off with the locking ring.



Before you install your nicely cleaned and lubed speedometer drive you most likely have to replace what's called a meter clutch. In this case the drive unit seized up with gunk and as a result wore down my meter clutch. You can see the meter clutch in this picture. It has the two prongs that fit in the above mentioned two slots of your input gear.



The clutch meter is responsible for transferring some of the energy from the front wheel to the speedometer drive, the drive divides the rotations to what the cluster accepts and transfers it to the cable and so and so forth.

Good luck.

P.S. chacal has the meter clutch as you probably will have to replace it if you have this problem. Page 5 of the catalog.

"HCP1797 OEM speedometer gear drive METER CLUTCH, this is the double-tanged metal washer that rotates along with the wheel and drives the gear unit. For all XJ550, XJ650, XJ750, XJ900RK, and XJ1100 models.
$ 3.00

HCP1798 OEM speedometer gear drive meter clutch RETAINER, flat washer that retains the above meter clutch. For all XJ550, XJ650, XJ750, XJ900RK, and XJ1100 models.
$ 2.50"

Edit:

Here's a picture of the new meter clutch next to the old one. The speedometer drive ripped or ground down the prongs. You can see how the prongs on the old one don't exactly have the same reach. If yours looks like this, you're going to have to replace it.

 

very nice write up. i am replacing the meter clutch tonigfht and tomorrow night if i dont finish. how does the big rubber seal in front of it come off? i dont want to break/tear that with a screwdriver but its stuck. am i missing something? the catalog says its a circlip type retainer? the entire rubber piece with it or just a circlip?

 

If that's the wheel bearing seal, and it's original, oh boy, it's stuck!!

Get creative with flat blade screwdrivers and spray penetrants, light taps and patience.

To the above text, Dawn and Simple Green can be replaced with more powerful solvents, Engine Degreaser and hand cleaner are on the next rung up the solvent and chemical ladder. (good thread topic?)

 

I stand corrected. its not stuck. I can get flat screwdriver between the rubber and the meter clutch (the thing with tangs) and pry it just with a slight twist of the screwdriver. however, it doesn't rise up evenly. the metal circlip (?) just bends so I'm not sure if I can take this part out with no any damage done to remove the meter clutch

how many other folks have to had to replace the tangs(meter clutch)?? I consistently had trouble keeping the cable spinning and its not the drive unit or the cable itself, and the gauges themself work just fine whenever I hook a drill the bottom portion and watch the needle rise like it should. only thought I had was the tangs were just a hair too short causing the unit to slip and not tell me my speed... so I ordered the meter clutch from Len a long time ago and now got to working on it

 

Often times what happens is that someone has the wheel off the bike, and when it is re-installed, the tangs are not oriented correctly and as soon as the forks are snugged down, the tangs get bent in and you end up with the same problem. Been there, found that.

dave f

 

so nobody else has had to change theirs? maybe since this thread is under suggestions I'll start my own thread if I have to

ya Dave, I know what you mean.. I've tried to keep that a non-factor but its really hard to mount the wheel back on while holding the drive unit and washer and feeding the axle bolt back thru the wheel! next time I'll get my dad's assistance

I'd like to get this figured out. clearly I don't have a picture to show you fellas but if it would help let me know. When I bought it (the meter clutch-washer type thing with tangs) from Len, he didn't have any other suggestions like he normally does if you tend to forget the common things that go along with what you need to replace. Plus I emailed him early this morning and haven't received word back from him surprisingly

 

Hey moellear

I'm sure you managed to get that seal out by now, did you get it in one piece or did you have to replace it? I'm gonna try to gently remove it tomorrow after soaking it tonight.

 

Please start your own thread if you have an issue that needs resolved. This one is three years old and Moellar hasn't been around in quite a while.
Any oil seal will need to be replaced with a new one after it is removed. The act of removal will damage it, particularly when it is more than 30 years old. Sometimes you get lucky if you're careful about how the seal is removed, but I'd only reuse a fairly (less than a year old) new one.