driving my av8, slowing for a turn, felt a light clunk, went around the corner, and then no go. The engine is still running normally & revs, the shifter feels normal, the clutch feels normal, but it wont go. I thought an axle had broken, but the hub and wheel hasnt come apart. Maybe an axle key? can they fall out?
You leave alot of room for guessing here. You may have to jack up the back end and do some of your own diagnosis. That way your not chasing your tail from well meaning sugestions. N.N.
Key can't "fall out" but can sheer. Jack up one rear wheel at a time car in gear. With hub cap off try turning wheel . If AXLE nut does not turn but wheel does bad key that side. If both wheels/axles turn something inside the axle busted most likely.
I've seen axle keys break at the vintage drag races. I would think if you broke an axle key you would see the axle nut turning while the wheel was standing still. You could have broken a spider gear since you were going around a corner at the time. This would act just like a broken axle but the axle would not come out. I'm ***uming this car has a closed driveshaft. Once you have determined it is not an axle key Jack up the car off the ground and with the trans in gear see if you can rotate both wheels in the same direction at the same time. You should not be able to turn them together. If they do turn remove the speedometer adaptor and see if you can see the driveshaft turning. You can also remove the shifter top and see if the gears are turning. Drain the gear oil out of the trans and the rearend and see if there is any metal in it. Jerry
ok- heres the latest- I checked to see if the nut, hub and wheel all turned together- they did. So I think that the keys are ok. Then I removed the speedo adapter to see if the driveshaft was turning. I started the engine, and put it in gear. the speedo gear in there was rolling over, so I have power that far. But, I hear a light rhythmic rubbing noise. Not loud, not sure where, or if its part of the problem. I then jacked up the rear so both wheels were off the ground, and rolled the rear wheels back and forth. They roll in opposite directions, which seems like normal differential action, and they seem mechanically connected. So I think the spider gears seem ok. So my thinking at this point is this: the driveshaft or ujoint is FUBAR. If the ujoint came apart or otherwise came off, it might account for the rubbing sound. Either way, I gotta pull the rear end out. Whadda think, is my logic sound?
Hey, Briz sounds like you are on the right track.Rear ends are not to big a job to pull, hope that will get you to a quick fix. Good luck ..............Jack
The u-joint is at the front of the driveshaft bolted to the transmission output shaft. The speedometer drive gear is behind the u-joint so if it is turning I would ***ume the u-joint is still intact. Broken driveshaft or maybe it snapped off the front of the pinion gear? Were you doing bad things to it when it broke? Tell the truth, were going to find out when you send us a picture of the broken part. Jerry
If the u-joint came apart you would not see the speedometer gear spinning. To me a rubbing sound would suggest that you either blew out the splines in the coupler or possibly an axle key. Do you still have the center bearing in your torque tube? that would hold everything in place if the coupler was bad. Jack each wheel off of the ground with the car in gear and see if you can move the wheel. I'm putting my money on the coupler I've pulled a few apart that seemed to be well on their way.
Kevin lee cold be heading in the right direction, If the pin wears out or breaks in the pinion to shaft coupler the coupler can become sloppy and the splines wear out and your rod will be a no go.
If you have a stock A rear axle there is no coupler ,shaft goes directly onto the pinion gear. Drop the rear and pull the torque tube first. If later V-8 style rear those do have a coupler.
You may have broken the key at the end of your driveshaft, if stock model A. Also may have broken the ring and pinion gears, but that would make a ton of noise. You can stick your finger in the oil drain hole and see if there are any big chunks. But yeah pull that torque tube apart first, then tear into the rearend. It shouldn't take that long to figure out what is happening.
No, really, I wasnt hammering on it at all- Im concerned about the rear spring hangers too much to do that. But thats another subject. Ok, 1930 model A pickup, 1940 front and rear axles, 1939 trans, 1950 8BA. Was built as a hot rod in the 50s, my father in law bought it in 1968, blew the engine in 1969, and it sat in an outbuilding on the farm till I realized it was there. ( The blowed-up engine was a 59AB) We fixed it up and tried to keep what was there, and made it all work, replacing the 59AB with the 8BA. We boxed the frame and hooked up the brakes- it had the 40 rear but the rear brakes werent hooked up- it only had the FRONT MECHANICAL brakes. We fixed that, using parts from a 1940 frame that was out behind the shop on the farm. Anyway, I didnt do too much to the rear end- just new brake components and seals, and a new ujoint. I didnt pull the torque tube, and I didnt know about a coupler or a center bearing. My money is on one of those at this point.
Well, I got it apart, and I found the problem. The splines on the back of the driveshaft are gone. But that happened a long time ago. Someone actually welded the driveshaft-to-pinion coupler to the driveshaft to repair it. It couldnt have been very strong, and the weld finally cracked all the way through. heres a photo of the driveshaft. http://s170.photobucket.com/albums/u256/brisby_rodbuild/?action=view¤t=photo.jpg My plan right now is to go out to the farm and see if I can find a suitable replacement. There are several banjo rears out in the boneyard of different vintages. Mine appears to have 6 splines on each end of the coupler. Is this a common style? Im told one of the rears in the boneyard is a model A. And, while Ive got you guys here, is there anything I should watch out for since Ive got the torque tube out? There is a roller bearing up near the front of the driveshaft, maybe I should replace that, although it looks in pretty good shape.
The Model A drive shaft will be different I would think that the coupler could be succesfully welded back on and by adding a few plug welds in the coupler area it would hold up just fine if done by a competent welder
I'm not sure what kind of combination of parts you have there but I‘m going to give this a try anyway (I got your photo off of photo bucket and transferred it here). The photo looks like this is or I should say was a '35-'36 Ford driveshaft that was shortened and adapted to fit what ever year rearend you have, it’s probably a ’37 to ’48. The '35-‘36 and some of the ‘37 and ‘38 rearends had driveshafts with a ten splined coupler welded to the rear of the tube, the coupler is part of the tube driveshaft. The ‘37-‘48 driveshafts are a solid piece of steel just like an axle, they have a separate six splined coupler that connects them to the pinion gear. When you install a Flathead V8 in a Model A it is a very common practice to install a later model rearend which is stronger than the Model A rearend. If it is a ‘39 to‘48 rearend then it comes with hydraulic brakes on it already so those were real popular rearends on hot rods in the 40s and 50s. A little about these rearends. The ‘39 rearend has a wide bolt pattern like an old Volkswagon, you can change the brake drums to get the smaller bolt pattern but back in the day most guys just went with the ’40 rearend because it had the smaller bolt pattern on it already that would accept the 16” '35 Ford and Kelsey wire wheels or the 16” ‘40 to ’48 Ford stamped steel disc wheels. The later 46-48 rearends are a little too wide for a Model A, people use them but they do not look as nice as the narrower ’40 rearends do. To put a later ‘37-‘48 rearend in a Model A causes a problem because the driveshaft and torque tube are too long so they need to be shortened. With care you can shorten the torque tube and weld it back together but the driveshaft is a problem. Since it is a solid shaft like an axle all you can do with it is shorten it and then have somebody that’s knows what they are doing cut new splines on it. The guy that built your rearend did not have anyway to shorten the solid driveshaft so he took a ‘35-’38 tube Driveshaft, shortened it and then welded it to the coupler. It wasn’t a bad idea but it does not look like he could weld real good and I have serious doubts that this thing was straight and balanced when he was done with it. It probably had a pretty good vibration at high speeds. I’m pretty sure your not going to find a driveshaft in your pile of rearends that is going to be the right length. The Model A rearend at the farm is going to have a solid driveshaft that looks like an axle. It has a tapered end with a keyway that goes into the pinion gear, just like an early Ford axle has. It’s not going to work with your rearend. Your going to need to make a new driveshaft or have yours re-welded, if its savable? You could try taking the tube and coupler to a driveline shop and see if they think they can do anything with it. The coupler should have been riveted to the pinion gear, if not make sure the splines are still good on the pinion gear and make sure you put a rivet back in the coupler when you put it back together. If it was me this is what I would do, this not cheap but I think it will be the best repair. Speedway offers a driveshaft kit. You cut the tube to the right length and then take it a driveline shop and have the rear spline welded on it. Its going to be at least a $400.00 project. Sell some of the stuff at the farm to pay for it. I have never had a driveshaft shortened for an Early Ford. I have always stuck the rearend in there that came with the car from the factory and it always seems to fit, imagine that. If any of you guys out there have shortened torque tubes and driveshafts let us know how you did it? Anybody know why that Speedway driveshaft kit won't fit a '39-'40 Mercury or '47-'48 Ford rearend? Why would a '39-'40 Mercury rearend be different than a Ford? Jerry
Mercury rear ends have no coupler - driveshaft is pressed right into the pinion. I've seen lots of ways to shorten a driveshaft and torque tube. The tube pretty straightforward. After cutting, use a big thick piece of angle to clamp the two halves back together and weld. With the solid driveshafts I have seen everything from a HUGE bevel, clamping to angle iron and welding back together. Shorten from one end and cutting new splines - careful here as some shafts are not a constant diameter the entire length. Making a coupler with several holes and rosette weld then weld around the ends. 33-34 driveshafts are as close to a cut and weld solution as you will find - this is what the Spadaro and Speedway cut to fit shafts are patterned after. Just don't overthink it. Make things the length they need to be and weld them back together. If I had your problem, I would just buy a new coupler and weld it to what you have as Russco suggested. No reason to throw away anything you have.
Im looking at this thing and I think thats whats happened- they shortened it to fit. The torque tube looks like its been cut down. hopefully theres a photo here showing a weld bead on the torque tube.
thought you might want to see what all this hardware came from... ( its not blowing smoke, it was cold that morning)
Even with the splines wasted on the driveshaft I think I would just grind all of the old weld off, drill several holes in the coupler then slide it back on. Weld through the holes and finish it off with a nice bead around the end.
Question. You didn't show the drive shaft. I ***ume someone cut the spliined end off to shorten it and more or less stub welded them together? I can't see how shaft splines could shear off enough for the shaft to spin in the coupler and the coupler splines look that good. If they DID shear off clean and wern't to sloppy in the coupler it could be plug welded. An old method that did work ok and was similar was to chuck the coupler in a lathe and bore the splines 1/2 way in the coupler to a press fit to the OD if the drive shaft . Then bore out the split pin holes on that end of the coupler to 1/2 inch and press the shortened to lengh drive shaft shaft in and plug weld it. Best fix would be find another shaft and get a good measurement of what you need and get it cut and replined. There are a couple of outfits in Spokane that do it if you can't find anybody down there.
Sorry, I missed the photo bucket picture. That looks like someone shortened it and ground it down and jammed it in and welded it. There would be a good chance that it was out of line and that put a strain on that **** weld. That shaft had to have been shortened somehow to fit an A. To have had splines there to wear off it would have either been replined poorly or cut and welded. I'd start with another shaft, they aren't that hard to come up with.
you brought up an excellent point- I cant trust the modified shaft to be true.So, if I weld the coupler to the shaft Ill have to make sure there isnt any runout on the ground-down part. Im thinking of maybe just having the shaft built up with weld and machined back down with splines. That way I wont have to worry about it being true or the welds holding up. I dont plan on running this old girl hard, but I do plan on driving her a lot. Anyway, Im torn between welding the coupler to the shaft (easier, I think) or having new splines machined in (more involved, maybe unnessessarily so, but maybe more durable.)
I just went through this on my AV8. Heres what I did to make sure it was true and strong. I took a 6 spline couplerr and the front of a 35-36 drive shaft to a machine shop. They took a hollow tube and machined each end to fit the splined ends I provided. Got it to the length I needed, trued it in a lathe and welder her up. Cost me 130.00 total.
The failure of the drive shaft was due to the lack of alignment of the torque tube ends after it was shortened. It is of utmost importance that the torque ball collar center line and the banjo collar center line be on the same axis after shortening. With a bearing supported drive shaft any off alignment creates a bowing of the driveshaft during rotation and this bow places a strain on the shaft at its weakest point until it self destructs. In this case the collar weld is the weakest link and therefore fatigued. You will need to recheck the center line of the torque tube before you proceeded or this will just happen again. You will also have to make sure that the replacement drive shaft spins on a true center, so just welding a new plug in the end of the old driveshaft may still be out of alignment.
The Jalopy Journal
