Mystery vibration at 25 mph can't be diagnosed. It's not the front end!

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The shop is right. The washers are not a "fix". They are a diagnosis tool. Listen to Dan. He is not blowing smoke up your skirt. Get the books he recommended. Read them. Learn how to diagnose and repair your car yourself. These things are like Fred Flinstone compared to new cars. A chimp can be trained to disassemble and reassemble them. It's not difficult. There are no magic tricks. There are no unknowns. You can learn to do every single diagnosis and repair all by yourself if you will simply listen to good advice.
 
RustyRatRod said:
The shop is right. The washers are not a "fix". They are a diagnosis tool. Listen to Dan. He is not blowing smoke up your skirt. Get the books he recommended. Read them. Learn how to diagnose and repair your car yourself. These things are like Fred Flinstone compared to new cars. A chimp can be trained to disassemble and reassemble them. It's not difficult. There are no magic tricks. There are no unknowns. You can learn to do every single diagnosis and repair all by yourself if you will simply listen to good advice.
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Re-read Bro, the shop refused to use the diagnosis tool the OP asked them to try. Nobody here said the washers were a fix, the OP understands this, the shop hasn't made
a diagnosis to solve it but refused to try something suggested to them. A prop-shaft swap w/a known good unit would be a good move if available,......relax a little.........
 
jeffrey356 said:
The rear end has been that high since I bought it. That was 4 years ago. The previous owner put truck(?) or station wagon(?) leaf springs on it because he said that he couldn't find new ones for the dart. Well, that was the next thing I was going to correct. I found the correct 5 leaf springs from classicindustries. I have had to chase down a ton of parts that were just slapped on it for a quick fix. That is just one example. The dart didn't start shuttering until about 3 months ago, but I will definitely get the proper leaf springs for it as soon as possible. Now I understand what he meant to DIAGNOSE the problem with washers. I told the SHOP to try that and they wouldn't do it. They said that's not a fix. But, I'll have it back next week and I can do what ever it takes as far as diagnostics. Believe me, I can't afford to just slap parts on it. I'll need a crawler first and maybe I can do it. I still have the physical limitations to deal with. If the washer diagnosis works then I'll know what the problem is and what I have to do to fix it once and for all. This has all been a nightmare because basically, I have just been the messenger. Each message I pass onto the shop, gets shot down. I couldn't just go out to the garage and try the possible solutions mentioned myself. I'm only out $100. That's labor, spark plugs and a whole lot of grief.
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As far as "couldn't find springs for the Dart" goes, that's flat out a bunch of bullshit....period. At no time has it been difficult let alone impossible to buy a set of A-body leaves.
If those are the wrong leaves, the axle position may not even be correct, either way that rear is 3-4 inches higher than stock. The front isn't too low, it's too angled down.
 
jeffrey356 said:
I found the correct 5 leaf springs from classicindustries.
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…for $450, it looks like. Ye gods. That's why you can't afford stuff! It's been awhile since I was in the market for Springs, but I think that price is way, far out of line, and that's because Classic Industries is not the smart place to go buy springs (or much of anything else). If you had posted on here and asked "Where should I buy springs for my car?", we would've pointed you here and here. Instead, what you did was Ready...FIRE!!!!...aim. And that's what it sounds like you're planning to do with your driveshaft. And although numerous people have spoon-fed you diagnostic procedures and other helpful information, you claim to be confused, want to know where to buy a reconditioned B&T, etc.

I repeat myself: You aren't following the good, clear, simple advice you're being given, so I give up. ¯\_(ツ)_/¯
 
Killer6 said:
Re-read Bro, the shop refused to use the diagnosis tool the OP asked them to try. Nobody here said the washers were a fix, the OP understands this, the shop hasn't made
a diagnosis to solve it but refused to try something suggested to them. A prop-shaft swap w/a known good unit would be a good move if available,......relax a little.........
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YOU re-read what I said. I said they were right when they told him it was not a fix and they were. I know eaxctly what I read. Do you?
 
I agree about the rake. It drives me crazy! It's not the 1970's. I found the proper 5 leaf springs right away. I think the previous owner put them on to look cool or something. Before this vibration issue became a nightmare, I had found the proper 5 leaf springs and was going to put them on. Now the ball will be back in my court and I will take my time and follow all advise. I'm really not as dumb as I appear, I just became the middle man in this affair and the mechanic wouldn't follow my leads. Everyone is plug and play these days. Knowing your old car is the best way to go. I agree with Dan, but was between a rock and a hard place. No more. The dart just purrs after I switched to electronic ignition and has only 43,000 miles on it. No smoke out the exhaust at all. Thanks everyone for your advise. jeffrey
 
I'm gonna to try a crawler to get under the car and attempt it myself. I will just take my time and go slow. My wife used to help me, but she's in heaven. So, I'll do what I can.
 
Firstly, I need to thank slantsixdan for the information provided. Now I can use it! The mechanics fought me the whole way. Done with that. Nope, I haven't bought the $449, 5 leaf springs yet. I just said that I found them right away because the rake has always bothered me. When I get there I'll put out feelers first on the forum and go from there. I'm not there yet! I want to have a smooth ride first. That is priority for the winter. Then I'll move on to the springs. Or I might just do them concurrently. I'm not blowing money yet on the parts. Yes the E3 spark plugs was a bad idea, but I have a neighbor that likes my car and he suggested them. No harm, no foul. I immediately told the shop to put the stock champion plugs back in.
 
RustyRatRod said:
YOU re-read what I said. I said they were right when they told him it was not a fix and they were. I know eaxctly what I read. Do you?
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Yes, the shop stated the obvious, which everyone here agreed on..............then refused to try a diag. technique, which everyone here agreed it is,........................
for someone unable/barely able to do so themselves,..and you..................
dog-chasing-tail.jpg
about that part.
How long could that've taken them to do for a customer that can't? That was the point. I guess I'll stop using jumper wires in relay sockets to diag. 'cause a jumper wire
ain't a fix.......................or shooting a squirt of brake clean in a non starter to see if its not getting fuel cause I can't keep up with the car can in hand.......................
 
Killer6 said:
Yes, the shop stated the obvious, which everyone here agreed on..............then refused to try a diag. technique, which everyone here agreed it is,........................
for someone unable/barely able to do so themselves,..and you..................View attachment 1715094530about that part.
How long could that've taken them to do for a customer that can't? That was the point. I guess I'll stop using jumper wires in relay sockets to diag. 'cause a jumper wire
ain't a fix.......................or shooting a squirt of brake clean in a non starter to see if its not getting fuel cause I can't keep up with the car can in hand.......................
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I think we both agree that we agree, so why the apparent argument? I also agree that the shop was pretty sorry for not trying the washers. 10 minutes at best. Pitiful.
 
Man, I stirred up a hornets nest! It's all over now. Conclusion; I correct rake, which has always bothered me ( to much 1970's bling), and then or at same time diagnose if B&T is a culprit with washers. If it is a problem, follow the instructions by slantsixdan to take to a well respected drive line specialist, that welds, and change B&T out. Seems like I can handle that. All I have is time. Thanks everyone. jeffrey356
 
I may not have the back trouble you have,but do have days when i would rather not work. It was after a fall off a ladder, back and neck injuries. Did my mom's block heater on the floor, and weeks later i got a hoist. Had to.
Hopefully you can find a FABO member nearby thats willing to help. So for some reason i have 4 creepers,wish i could just give you one.
I know its just one picture, but that is a nice looking ride.
 
B&T is 2 rollers on a shaft and a receiver. If you cant shake the driveshaft back and forth/up and down along the plane of the balls or rotationally at the trans output shaft, the B&T is probably not at fault, these were installed behind street hemis in heavy cars so they can take some torque. IF the B&T has worn itself a groove due to lack of lube from a disintegrating 50 year old rubber/leather sack (likely) the washers will move the receiver a few mm down its length to virgin territory. A 4X4 shop can make you a splined driveshaft that will bolt up to your old flange and rear end. MP used to sell the kit for this so its a legit conversion. IF your mechanic sensed a vibe at speed with the driveshaft removed (?) then its not the reason for THAT issue logically. I would start to investigate myself with little effort here: remove the belt(s) and rev the motor to replicate that vibration. Could be nothing but a bent fan or water pump bearing. The ignition upgrade sounds like it went great. IS this a manual trans? IF it were an automatic, Id tell you to check the convertor bolts and the flex plate. all convertors have balance weights on them. Id look while I was down there for any unpainted areas on the convertor perimeter for traces of a weight that was flung off. The timing chain is unlikely going to cause a ignition issue dramatic enough to cause a vibration. These slants are pretty low tech when it comes to tolerances in most all areas, 'cept maybe valve lash. They were made tough for all kinds of applications. I had my first high school 65 up that high for tire reasons (they were too wide) and I think I always had a nagging shudder at some speed, most likely due to the angle of the pinion compared to the angle of the trans output shaft. There is a tolerable range for any double U-joint (its rotation/speed variance can be likened to a sineusoidal wavelength) but Im not 100% sure it applies to the CV of the B&T. Hey, you know you can only do so much with a nackered back, so take our suggestions to heart if you cant physically do the work yourself. You know, Id trust a 50 year old mechanic too, unless he was admitedly clueless to that design. Those guys see far more trouble than we do on a daily basis (unless one of us is a mechanic too).
 
Killer6, I have read it thoroughly and had to stop the bleeding with that shop. A week ago, I told them to check the harmonic balancer and the torque converter. They told me that labor at $70 per hour would cost over the dollar limit that I gave them. As usual, The lead said he didn't believe it was the harmonic balancer. UGH! I'm picking it up on Monday morning. I'm tired of them telling me it's none of the things I suggest. So, it's on me now. I will take my time and work through all the advise on this forum. Time will tell.
 
Ha! Now they are on-board. Finally, the owner was asking all the right questions. Ignition! That was a crazy direction they took. The engine purrs. I collected the keys and said, "see ya." I've had it in storage so long, I never bothered to look at the leaf springs. Yes the previous owner put six leaf springs on it. It should be 5 leafs. That will drop it to the proper rake. I had 3 people stop me and ask all about it when I was at gas station and Wal-Mart. Now I can take it real slow because of my physical condition and look everything over. It's my call now.
 
I think we have some members in Missouri. Maybe one of them would be good enough to come take a look with you.
 
slantsixdan don't give up on me now. It's all mine now. Yes you saved me 50% on 5-leaf conversion. Now, it's time to check the B&T. I do have the factory service manual you suggested. It tells me the exact torque on the front and back bolts of the driveshaft. Good info. I want to thank Pishta for the automatic trans converter bolts and flex plate information. I didn't know there was balance weights on the converter. That sounds right because it just starting doing this 3 or 4 months ago out of nowhere. It seems that something like balance weights were maybe flung off. Dart only shutters at 25 mph which is probably it's harmonic vibration that all cars go through when fired up cold. The shop was wrong. I ran it up in neutral and park and there was no vibration. When I picked it up, the owner conceded the fact that it is indeed a drive line problem. Good thing I stopped them from going any further. Yes, I will consider going to a 4X4 shop or drive line specialist to just dump the B&T if I feel that it is the problem after diagnostics.
 
I've never seen weights fall off a converter. I have seen a lot of vibration at a speed be it 25 mph, 35 mph, 60 mph, whatever,,, and it has usually been driveline components like U joints. I remember one chevy work van that belonged to a TV repair shop across the street from this shop. The owner complained of a vibration right at 50 mph, not 45, not 55. I never felt it during the test ride, even when he asked, "Did you feel that?".
I took the driveshaft out and felt no problem working the U joints around in hand. My shop owner/bossman said, "I already sent Jake after new joints for it. Hell, Blanton's got money". So during my taking the joints out... WHOOT there it is! Just 1 of the 4 little shafts marked up pretty good. Then the boss said something like "He knows his van like he knows his wife. The customer is always right."
My point being,,, Eventually the fault will get bad enough that anyone could easily diagnose. So keep hunting and guessing or just drive it waiting for the fault to truly shows itself? That's your decision.
Heavier duty springs have a different sag rate but shouldn't make a difference in normal ride height. Maybe the 6 leaf springs were re-arched or otherwise not correct for your vehicle.
 
I think redfish is on to something, up on hoist,likely not in neutral shop gave driveshaft a shake and determined no further investigation was necessary. Telltale will be wrench marks on nuts and bolts that hold shaft in, or lack thereof. Price of a good quality u-joint is money well spent for peace of mind. Then slipping ball/trunnion apart for inspection will at least help you rule it out.

Cant stress enough how important good safety stands are at this point. Good luck.
 
jeffrey356 said:
Killer6, I have read it thoroughly and had to stop the bleeding with that shop. A week ago, I told them to check the harmonic balancer and the torque converter. They told me that labor at $70 per hour would cost over the dollar limit that I gave them. As usual, The lead said he didn't believe it was the harmonic balancer. UGH! I'm picking it up on Monday morning. I'm tired of them telling me it's none of the things I suggest. So, it's on me now. I will take my time and work through all the advise on this forum. Time will tell.
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Lol! That was directed at slantsix64, not Yourself sir, as they asked questions already asked &/or addressed.
 
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