MGB & GT Forum

Welcome! Sign In Register

Please Sign In or Register to Search

Speedometer problem

Posted by CtCarGuy

Want to advertise your business in this space? Click here for more information!

Topic List Forum List Newer Older Start New Topic

Speedometer problem #1
CtCarGuy Larry Boardman Simsbury, Connecticut, USA	Posted: March 06, 2013 07:07PM Registered: 3 months ago Posts: 14

The speedometer in my 70B was not working when I got it. I checked the angle drive on the transmission and the drive into the transmission was distroyed. I think the previous owner did not put in the washer. I put in a new angle drive (with washer) and now the speedometer jumps all over. The cable is good with no kinks and is lubricated. I took the speedometer out and made a tool the same size as the cable end and used a drill at very low speed to see if it was the speedometer/speedometer angle drive. It ran perfectly.

I am now concerned the pinion gear in the transmission is bad, maybe missing a tooth or 2. Replacing it crates 2 problems. 1) I cannot get the drain plug out of the transmission. I think the steel/aluminum corroded. I am concerned with putting too much force on it. I don't want to crack the housing. 2) The second problem seem to be that Moss and BV don't list the pinion or gear. In order to pass inspection the speedometer must work.

Thanks in advance for the help. The car is coming along great so far. Just these little gremlins that keep appearing.

Larry

Sponsored Links. You can hide this ad & support this site by upgrading to a Gold Membership ~ click here for more info.

Reply Quote

Re: Speedometer problem #2
chris Chris Roop Pendleton, OR, USA	Posted: March 06, 2013 07:11PM Registered: 14 years ago Posts: 30,222

You don't need to drain the trans to replace the gear in the trans. I would look to the cable for dirt, broken strands, etc. first. If that is fine, then pull the gear housing and check the gear. They can be bought used on the trader or some such.

How to advertise on this website

Roop's MG – Pendleton, OR USA Check out the Vendors' Deals page for the clutch, brake, and water pump sale. Please email me at the business address for business concerns.

Reply Quote

Re: Speedometer problem #3
ozieagle Herb Adler Geelong Victoria, Australia 1958 Wolseley 1500 "Wooly" 1966 MG MGB "Bl**dy B"	Posted: March 06, 2013 11:23PM Registered: 2 years ago Posts: 1,349

It could also be gunk in the speedo input bearing. The drill has enough torque to overcome it, by the cable drive, being somewhat springy, winds up till the gunk lets go and then the cable unwinds, giving a high reading, to only stall again, once it has unwound. Then repeats, giving a waving needle.

I hope all that makes sense.

Herb

Reply Quote

Re: Speedometer problem #4
CtCarGuy Larry Boardman Simsbury, Connecticut, USA	Posted: March 07, 2013 06:01PM Registered: 3 months ago Posts: 14

Thanks Herb:

We actually tried turning the right angle drive on the speedometer by hand and had very little resistance. The action was smooth and the needle steady. I pulled the cable out from the speedo end and it was well lubricated with no kinks or strands. Looked perfect. I held one end and my friend the other. He twisted his end and there was no slack felt. The more I get into it, the more I think its the gear in the transmission. The next test will be to drive the car with the speedometer out and feel the action of the cable. I did test the cable when I put in the lower angle drive and it was smooth.

I think its interesting that the reproduction houses don't offer the pinion or gear based on the material used. I would think that there parts would be in demand.

Larry

Sponsored Links. You can hide this ad & support this site by upgrading to a Gold Membership ~ click here for more info.

Reply Quote

Re: Speedometer problem #5
CtCarGuy Larry Boardman Simsbury, Connecticut, USA	Posted: March 07, 2013 06:05PM Registered: 3 months ago Posts: 14

Hi Chris:

Thanks for the reply. I thought I read somewhere that if you remove the plate where the speedometer cable enters the transmission, the oil will come out. I would love to change it be the drain plug is corroded in place. I imagine filling it from inside the car behind the console is going to be fun.

Thanks

Larry

Reply Quote

Re: Speedometer problem #6
chris Chris Roop Pendleton, OR, USA	Posted: March 07, 2013 07:45PM Registered: 14 years ago Posts: 30,222

Jack up just the one side to be sure. As for checking the cable, pull it out of the housing and look carefully. Good luck!

How to advertise on this website

Roop's MG – Pendleton, OR USA Check out the Vendors' Deals page for the clutch, brake, and water pump sale. Please email me at the business address for business concerns.

Reply Quote

Re: Speedometer problem #7
ClayJ Clay Johnston Mt. Olive, MS, USA 1972 MG MGB	Posted: March 07, 2013 07:48PM Registered: 7 years ago Posts: 7,351

First, replace the cable; may/may not fix the issue but its the least expensive, most direct.

Someone posted a PDF recently on attempting to repair a waveing needle.

Nisonger can fix the waveing.

Sponsored Links. You can hide this ad & support this site by upgrading to a Gold Membership ~ click here for more info.

Reply Quote

Re: Speedometer problem #8
ozieagle Herb Adler Geelong Victoria, Australia 1958 Wolseley 1500 "Wooly" 1966 MG MGB "Bl**dy B"	Posted: March 07, 2013 08:21PM Registered: 2 years ago Posts: 1,349

Hi again, Larry,

A thought I had, about testing, is to use the cable attached to the speedo and run it with the drill. This would clear or condemn the whole cable / speedo bit.

Herb

Reply Quote

Re: Speedometer problem #9
CtCarGuy Larry Boardman Simsbury, Connecticut, USA	Posted: March 10, 2013 05:37PM Registered: 3 months ago Posts: 14

Thanks for all of the help. The speedometer tested fine using a drill to drive it. I pulled out the cable again but this time cleaned all of the lubricant off it and lightly machine wire brushed it ti see if there were any kings or frayed windings. It looked fine and I re-lubricated it and installed it. I was careful not to over tighten the connection into the angle drive on the speedometer. I wanted to be sure the nylon collar on the cable was not binding. Bottom line is it works great with only a very slight waiver.

Larry

Reply Quote

Re: Speedometer problem #10
CtCarGuy Larry Boardman Simsbury, Connecticut, USA	Posted: April 19, 2013 08:09AM Registered: 3 months ago Posts: 14

Here we go again. The speedometer worked fine for awhile and then quit again. We pulled the lower angle drive and the transmission end was ripped like the one we took out. The car is a 1970. Can the lower (and upper) angle drives be removed? The cable looks perfect. We tried turning the cable from the transmission end by hand and it seems stuck?? Both angle drives were checked and the bottom washer is in place. Both angle drives turn fairly easily by hand and the speedometer internals are free. Next is to check the cable with both ends disconnected to check for a krimp in the sheath. I do remember it was a little hard pushing the cable into the sheath for a bit and then it went in easily.

Thanks in advance for the help.

Larry

Reply Quote

Re: Speedometer problem #11
ClayJ Clay Johnston Mt. Olive, MS, USA 1972 MG MGB	Posted: April 19, 2013 09:32AM Registered: 7 years ago Posts: 7,351

Larry,
Wonder if the cable sheathing has an issue?

One option, is to replace the cable and angle drives with a OD cable and no angle drives.

One other thing. I was having problems with my speedo acting inconsistently. I found that if the night-light fitting is pushed completely into the speedo the end of the bulb will hit the speedo pickup.

Reply Quote

Topic List Forum List Newer Older Start New Topic

RSS

Add your reply here, or post your own questions!

Members Sign In if you've already registered, or
Register a New Account
Registration is free and takes less than a minute

MGB & GT · MG Midget · Buy, Sell & Trade · Vendor & Group Buy · MG Engine Swaps · Original MG · MGA · MGC · MG Magnette · 1100 & 1300 · T-Series & Prewar · Modern MGs · MG Motorsports · MG-2013 Event · Member Meetup · Other Vehicles · Off Topic · Clubs

Having trouble posting or changing forum settings?
Check the Forum Help File (FAQ) or contact the webmaster.
View the archived version of this thread.
Built using Phorum Open Source Software

The MG Experience

www.mgexp.com

MGB & GT Forum

Speedometer problem

Add your reply here, or post your own questions!Members Sign In if you've already registered, orRegister a New AccountRegistration is free and takes less than a minute

Join Our Club

MGExp Menu

—

Adjust Text Size

More to Explore

Add your reply here, or post your own questions!

Members Sign In if you've already registered, or
Register a New Account
Registration is free and takes less than a minute