The Ford Barn

woodrow · 12-02-2013, 09:40 AM

When I got the "new" '31 Model A last week the speedometer didn't register so I've been messing with it to see what is needed. Yesterday I removed the cable and speedometer head and the gear drive that fits on the drive shaft. I see that the speedometer head does work. I made a little gizmo that's the size of the end of the cable that goes into the head, put my power drill on it in rerverse and it registers just fine. This morning I put the power drill on the end of the cable that fits on the gear drive and the other end back into the head, spun the cable in reverse and it works fine. When I removed the gear drive from the drive shaft I noticed the cap that screws the end of the cable to the gear drive was broken, however both ends of the cable were in the head as well as the gear drive but it didn't register when I drove the car. I'm wondering if the teeth on the gear drive were not messed with the gear on the drive shaft---how can I check that? I see there is a thin gasket still in place on the drive shaft where the gear drive fits but I didn't remove it since I didn't want to mess it up. I'm open to suggestions as to what I should do next. Thanks

Kevin in NJ · 12-02-2013, 10:26 AM

How about go check out the webpage that Bob was nice enough to put online:

Bob's Speedometer collection of articles

woodrow · 12-02-2013, 05:10 PM

Checking the speedometer head---it seems to be working okay. The gear that attaches to the drive shaft was removed and inspected. It does mesh with the drive shaft. Seems the big problem was a bad cable assy. Just ordered one and we'll see if that works. Thanks for all the help. I appreciate it.

Smurkey · 12-03-2013, 10:18 AM

I had a problem with the cable sliding too deeply into the transmission drive wherein it would then disengage from the speedo head, All of this inside the cable housing, so it was not evident. I bent a small piece of wire into a tight "U" shape and stuck it in the transmission gear housing where the cable inserts so it could not go in so deeply. Has worked fine ever since.

gadgetgeeza · 12-19-2013, 11:44 AM

1930 Coupe - interested in your comment that the gear housings are different for each gear tooth size. I have a similar problem to Woodrow - drive isn't meshing properly. I have a standard 1929 so it has a new 18 tooth drive gear which isn't meshing. The gear housing has 21 cast onto it - is this the intended gear size? if so an 18 tooth gear will be smaller and won't mesh. Where do I get an 18 tooth gear housing from? they all look the same/no choice on all the suppliers catalogues.

gadgetgeeza · 12-19-2013, 02:05 PM

Sponsored Links (Register now to hide all advertisements)

That's really helpful 30 Coupe. So now I understand the problem which confirms my suspicions. I definitely have the wrong housing which is marked 21 - presumably for a 21 tooth gear. So where do I get a speedo drive housing marked 34-9 (or possibly 18) from? Is there a way of identifying one from another without a mark?

gadgetgeeza · 12-19-2013, 02:49 PM

I have seen a reference (can't remember where) that the new housings are to be fitted with up to three gaskets. That would possibly explain different gear sizes. Having just bought a new gear and shaft, I am tempted to just buy a new housing - they must only have one size manufactured.

gadgetgeeza · 02-17-2014, 03:42 PM

Update - I fitted a standard speedo gearbox today and hey - it works!! Great relief. Haven't checked the accuracy yet but the gauge looks steady.

Drive Shaft Dave · 02-17-2014, 09:34 PM

The cable I just got from Bert's came with a spacer 3/16 x 3/8. Note, some early drive gears with the deep hole will require this spacer be dropped in first.

Drive Shaft Dave · 02-17-2014, 10:34 PM

I should have mentioned that this was an instuction sheet that came with the cable. Was this for a slightly shorter cable? Thanks for the photos and charts.

Drive Shaft Dave · 02-18-2014, 12:10 AM

30 Coupe, thanks a million for the photos, and the excellent advice.

Drive Shaft Dave · 02-18-2014, 12:34 AM

With the cable I am using , round keyed end, cable connected to speedometer I get about an inch of free play. Is it ok to use several washers?

Drive Shaft Dave · 02-18-2014, 01:28 AM

I will go with the washer's thanks again for the prompt reply.

fordcoupe · 02-18-2014, 09:13 AM

This is good information thank you for sharing i have to work on my 28 truck this spring the speedo is not working thanks for sharing.

BlueSunoco · 02-18-2014, 10:56 AM

Woodrow, I'd be careful chucking a Model A speedo into a power drill to test it. I was always told that the gearing inside is too delicate to handle this.

Anyone out there concur? I may be all wet, but I was told that years ago by a local antique car restorer who is now dead, he really seemed to know his stuff so when he told me things like this they stuck with me a LONG time

Drive Shaft Dave · 02-18-2014, 11:40 PM

30 Coupe, I put one washer in , and end play is ok. I can pull on the cable and the speedometer does not disengage, so i am good to go. Thanks again.

burner31 · 11-09-2015, 09:11 AM

Going to be re-doing my speedo this Winter, good stuff here thanks

glenn in camino · 11-09-2015, 08:50 PM

find a different cap. I broke one once and found that they are not available from the parts suppliers. Look for a used cap on an original cable.

12-02-2013, 09:40 AM	#1
woodrow Senior Member Join Date: Apr 2012 Posts: 141	Model A speedometer question When I got the "new" '31 Model A last week the speedometer didn't register so I've been messing with it to see what is needed. Yesterday I removed the cable and speedometer head and the gear drive that fits on the drive shaft. I see that the speedometer head does work. I made a little gizmo that's the size of the end of the cable that goes into the head, put my power drill on it in rerverse and it registers just fine. This morning I put the power drill on the end of the cable that fits on the gear drive and the other end back into the head, spun the cable in reverse and it works fine. When I removed the gear drive from the drive shaft I noticed the cap that screws the end of the cable to the gear drive was broken, however both ends of the cable were in the head as well as the gear drive but it didn't register when I drove the car. I'm wondering if the teeth on the gear drive were not messed with the gear on the drive shaft---how can I check that? I see there is a thin gasket still in place on the drive shaft where the gear drive fits but I didn't remove it since I didn't want to mess it up. I'm open to suggestions as to what I should do next. Thanks

12-02-2013, 10:26 AM	#2
Kevin in NJ Senior Member Join Date: May 2010 Location: South East NJ Posts: 3,398	Re: Model A speedometer question How about go check out the webpage that Bob was nice enough to put online: Bob's Speedometer collection of articles

12-02-2013, 05:10 PM	#3
woodrow Senior Member Join Date: Apr 2012 Posts: 141	Re: Model A speedometer question Checking the speedometer head---it seems to be working okay. The gear that attaches to the drive shaft was removed and inspected. It does mesh with the drive shaft. Seems the big problem was a bad cable assy. Just ordered one and we'll see if that works. Thanks for all the help. I appreciate it.

12-03-2013, 10:18 AM	#4
Smurkey Senior Member Join Date: Nov 2011 Location: Esko, MN Posts: 257	Re: Model A speedometer question I had a problem with the cable sliding too deeply into the transmission drive wherein it would then disengage from the speedo head, All of this inside the cable housing, so it was not evident. I bent a small piece of wire into a tight "U" shape and stuck it in the transmission gear housing where the cable inserts so it could not go in so deeply. Has worked fine ever since.

12-19-2013, 11:44 AM	#5
gadgetgeeza Member Join Date: Dec 2013 Location: Peak District, UK Posts: 45	Re: Model A speedometer question 1930 Coupe - interested in your comment that the gear housings are different for each gear tooth size. I have a similar problem to Woodrow - drive isn't meshing properly. I have a standard 1929 so it has a new 18 tooth drive gear which isn't meshing. The gear housing has 21 cast onto it - is this the intended gear size? if so an 18 tooth gear will be smaller and won't mesh. Where do I get an 18 tooth gear housing from? they all look the same/no choice on all the suppliers catalogues.

12-19-2013, 02:05 PM	#6
gadgetgeeza Member Join Date: Dec 2013 Location: Peak District, UK Posts: 45	Re: Model A speedometer question Sponsored Links (Register now to hide all advertisements) That's really helpful 30 Coupe. So now I understand the problem which confirms my suspicions. I definitely have the wrong housing which is marked 21 - presumably for a 21 tooth gear. So where do I get a speedo drive housing marked 34-9 (or possibly 18) from? Is there a way of identifying one from another without a mark?

12-19-2013, 02:49 PM	#7
gadgetgeeza Member Join Date: Dec 2013 Location: Peak District, UK Posts: 45	Re: Model A speedometer question I have seen a reference (can't remember where) that the new housings are to be fitted with up to three gaskets. That would possibly explain different gear sizes. Having just bought a new gear and shaft, I am tempted to just buy a new housing - they must only have one size manufactured.

02-17-2014, 03:42 PM	#8
gadgetgeeza Member Join Date: Dec 2013 Location: Peak District, UK Posts: 45	Re: Model A speedometer question Update - I fitted a standard speedo gearbox today and hey - it works!! Great relief. Haven't checked the accuracy yet but the gauge looks steady.

02-17-2014, 09:34 PM	#9
Drive Shaft Dave Senior Member Join Date: Dec 2011 Location: New hope Minnesota Posts: 742	Re: Model A speedometer question The cable I just got from Bert's came with a spacer 3/16 x 3/8. Note, some early drive gears with the deep hole will require this spacer be dropped in first.

02-17-2014, 10:34 PM	#10
Drive Shaft Dave Senior Member Join Date: Dec 2011 Location: New hope Minnesota Posts: 742	Re: Model A speedometer question I should have mentioned that this was an instuction sheet that came with the cable. Was this for a slightly shorter cable? Thanks for the photos and charts.

02-18-2014, 12:10 AM	#11
Drive Shaft Dave Senior Member Join Date: Dec 2011 Location: New hope Minnesota Posts: 742	Re: Model A speedometer question 30 Coupe, thanks a million for the photos, and the excellent advice.

02-18-2014, 12:34 AM	#12
Drive Shaft Dave Senior Member Join Date: Dec 2011 Location: New hope Minnesota Posts: 742	Re: Model A speedometer question With the cable I am using , round keyed end, cable connected to speedometer I get about an inch of free play. Is it ok to use several washers?

02-18-2014, 01:28 AM	#13
Drive Shaft Dave Senior Member Join Date: Dec 2011 Location: New hope Minnesota Posts: 742	Re: Model A speedometer question I will go with the washer's thanks again for the prompt reply.

02-18-2014, 09:13 AM	#14
fordcoupe Senior Member Join Date: Sep 2012 Location: pennsylvania Posts: 156	Re: Model A speedometer question This is good information thank you for sharing i have to work on my 28 truck this spring the speedo is not working thanks for sharing.

02-18-2014, 10:56 AM	#15
BlueSunoco Senior Member Join Date: Sep 2013 Location: Windy City Posts: 937	Re: Model A speedometer question Woodrow, I'd be careful chucking a Model A speedo into a power drill to test it. I was always told that the gearing inside is too delicate to handle this. Anyone out there concur? I may be all wet, but I was told that years ago by a local antique car restorer who is now dead, he really seemed to know his stuff so when he told me things like this they stuck with me a LONG time

02-18-2014, 11:40 PM	#16
Drive Shaft Dave Senior Member Join Date: Dec 2011 Location: New hope Minnesota Posts: 742	Re: Model A speedometer question 30 Coupe, I put one washer in , and end play is ok. I can pull on the cable and the speedometer does not disengage, so i am good to go. Thanks again.

11-09-2015, 09:11 AM	#17
burner31 Senior Member Join Date: Dec 2014 Location: Shawnee, Ok Posts: 3,471	Re: Model A speedometer question Going to be re-doing my speedo this Winter, good stuff here thanks __________________ Keith Shawnee OK '31 SW 160-B

11-09-2015, 08:50 PM	#18
glenn in camino Senior Member Join Date: May 2010 Location: Camino, CA. Posts: 3,086	Re: Model A speedometer question find a different cap. I broke one once and found that they are not available from the parts suppliers. Look for a used cap on an original cable.