Shortening a driveshaft yourself

Posted By: VITC_GTX

Shortening a driveshaft yourself - 11/11/11 10:31 PM

If I grab a C-body driveshaft would I be able to carefully cut the yoke off of one end, shorten the tube the appropriate amount and then reweld the yoke back on without worrying about balance? Any thing else I am not thinking of?

Posted By: burdar

Re: Shortening a driveshaft yourself - 11/11/11 10:35 PM

I had a driveshaft shortened at a metal fab shop once. What you described is exactly what they did. I never had it ballanced and didn't have any problems. Obviously the proper way is to have it ballanced. I'm sure I just got lucky.

Posted By: JohnRR

Re: Shortening a driveshaft yourself - 11/11/11 10:39 PM

Quote:

I had a driveshaft shortened at a metal fab shop once. What you described is exactly what they did. I never had it ballanced and didn't have any problems. Obviously the proper way is to have it ballanced. I'm sure I just got lucky.

How fast did you drive the car wit hthat unbalanced shaft ? The only time I ever had it done the balance seemed ok at the legal speed limit , 100mph with a 3.23 gear and a 4 speed was a completely different matter .

Posted By: burdar

Re: Shortening a driveshaft yourself - 11/11/11 10:58 PM

It was in a Cordoba I raced at the drag strip. 106mph with 4.10 gears and didn't vibrate that I noticed. Again, my experience is not typical.

Posted By: scratchnfotraction

Re: Shortening a driveshaft yourself - 11/11/11 11:01 PM

Quote:

Quote:

I had a driveshaft shortened at a metal fab shop once. What you described is exactly what they did. I never had it ballanced and didn't have any problems. Obviously the proper way is to have it ballanced. I'm sure I just got lucky.

How fast did you drive the car wit hthat unbalanced shaft ? The only time I ever had it done the balance seemed ok at the legal speed limit , 100mph with a 3.23 gear and a 4 speed was a completely different matter .

this is not a place to cut corners. IMHO

ever have a shaft come out at trip diget speeds

you need a least a lathe,then mill the weld bead only to remove the yoke,make the tube cut with the lathe also,then replace the yoke and phase it back to the other end,reweld it,only way i know to get it straight..then have a high speed balance to check the run out.

my local machine shop chops them down 25$ but i have to go to the drive shaft shop for balance at another 40$

$ well spent in my book

Posted By: Challenger 1

Re: Shortening a driveshaft yourself - 11/11/11 11:02 PM

I would think if you put it back like it was it should still be balanced or close?

Posted By: 68shifter

Re: Shortening a driveshaft yourself - 11/11/11 11:10 PM

I have done hundreds with a dial indicator, a home made jig to roll everything, and checking and rechecking. Most shafts pull loads of 250k along with multiple car shafts. Never has one come back.
The lathe makes cleaning the weld off easier but some time and a cut off wheel will work too. Quality and consistency of the weld is very important to the balance,
I have seen slot of shafts need balanced just because of how some idiot welded them.

Good luck, be safe with it.

Posted By: Sixpak

Re: Shortening a driveshaft yourself - 11/11/11 11:10 PM

If you had a lathe you might be able to DIY everything but the balance job. W/O the lathe I wouldn't chance it.

Posted By: burdar

Re: Shortening a driveshaft yourself - 11/11/11 11:11 PM

It was a metal fab shop so they probably did have a lathe. At first the car only went 89mph in the 1/4. When I stopped racing it was up to 106mph. That was a long time ago and the car has since been parted out.

Posted By: scratchnfotraction

Re: Shortening a driveshaft yourself - 11/11/11 11:13 PM

doing it and getting away with it and doing it right are 2 diff things.

the yokes have to be phased

the end welds need milled not cut with a hacksaw

needs a dail indicator to make sure it straight on the run out

yes you could be close to the balance it once had,but it has now changed with the cut and reweld bead

all this will make the u-joint have a longer service life,and stay in the car at high speeds

I have hacked shafts up and even welded u-joint caps into yokes after grinding the yokes to get them to angle more with out binding on a lot of 4x4 junk.

after throwing one at 105 mph on I-75 in a 73 duster, i wont ever skimp on a shaft again.

not saying you cant do it and get away with it..but it can bite back at ya

Posted By: 70Cuda383

Re: Shortening a driveshaft yourself - 11/11/11 11:24 PM

unless you have some REALLY good equipment at home, I wouldn't even chance it.

$300 to build a whole new driveshaft, or $100 to cut one down and rebalance it at just about any local clutch/driveline shop seems like small change when you're spending thousands on a car and it's drivetrain.

Posted By: John_Kunkel

Re: Shortening a driveshaft yourself - 11/12/11 12:05 AM

The reality is that most driveshaft tubing isn't all that round so dial indicating is useless and the method of separating the tubing end is irrelevant as long as the end is reinstalled in phase and equidistant with the other.

Posted By: scratchnfotraction

Re: Shortening a driveshaft yourself - 11/12/11 12:22 AM

thats kinda getting back to "getting away with it" no?

the tube end does need a nice straight cut to seat the yoke and help phase it I would think.

set it up,spin it,tap tap,spin,tap tap,spin,tap tap,spin,all phased and straight,now spin and weld..

Posted By: VITC_GTX

Re: Shortening a driveshaft yourself - 11/12/11 04:30 AM

The masses have spoken. I guess this will be one thing that I don't attempt myself.

Thanks to all.

Posted By: slantzilla

Re: Shortening a driveshaft yourself - 11/12/11 12:24 PM

We did a couple in my buddy's home shop many years ago with a small metal band saw and a stick welder, cutting the factory weld with a hack saw.

Scribe a line on the shaft and yoke and you can get it back in the right position.

Biggest problem we ran into was that some shafts had an inner tube that was a real PITA to cut down.

Never had one break, and one was in a pig block 4 speed car.

We did them ourselves mainly because there wasn't a driveline shop within 50 miles of us.

Posted By: daniel_depetro

Re: Shortening a driveshaft yourself - 11/12/11 01:50 PM

I've done a few myself and must have got lucky.

I simply scribed a lineup mark on the shaft/end and cut through the weld with a cut off tool.
I then cut the driveshaft the desired amount. On the last shaft that I cut I also had to relocate the attached weight.
I grinded down the weld smooth with a standard 4.5" hand held grinder.

Is it precise? No.
Is it perfectly balanced? No.
Can I feel any vibrations or any other adverse effects? No.
Does it work for me? Yes.

This is my personal experience and opinion. Take it for what it;s worth. It plus $1.10 will get you a cup of coffee.

Posted By: Finoke

Re: Shortening a driveshaft yourself - 11/12/11 02:32 PM

Has anyone tried this driveshaft kit? I've been thinking of doing that for my small to big block conversion.

Driveshaft kit from Mancini's

Posted By: JohnRR

Re: Shortening a driveshaft yourself - 11/12/11 02:46 PM

Quote:

Has anyone tried this driveshaft kit? I've been thinking of doing that for my small to big block conversion.

Driveshaft kit from Mancini's

That was never balanced to begin with so I doubt it would even be close ...

But it seems the overwhelming response is to just weld it up an go ...

I guess we can put driveline shops right up there with automotive machine shops , balancing is just another money grab ...

Posted By: 70Cuda383

Re: Shortening a driveshaft yourself - 11/12/11 02:53 PM

Quote:

Quote:

Has anyone tried this driveshaft kit? I've been thinking of doing that for my small to big block conversion.

Driveshaft kit from Mancini's

That was never balanced to begin with so I doubt it would even be close ...

But it seems the overwhelming response is to just weld it up an go ...

I guess we can put driveline shops right up there with automotive machine shops , balancing is just another money grab ...

well then, they're grabbing my money! got a rotating assembly there now getting re-balanced...factory crank/balancer/flexplate with new rods and pistons.

Posted By: ledft79

Re: Shortening a driveshaft yourself - 11/12/11 03:04 PM

I had a welding shop cut the shaft on my 70 cuda, when I switched from a 318 to a 440. That was back when I was a kid and drove like nothing else mattered. It was topped out and close to topped out many times, and I don't remember there being any vibration at all. Lathe or no lathe, I don't know.

Posted By: scratchnfotraction

Re: Shortening a driveshaft yourself - 11/12/11 03:37 PM

Quote:

Quote:

Has anyone tried this driveshaft kit? I've been thinking of doing that for my small to big block conversion.

Driveshaft kit from Mancini's

That was never balanced to begin with so I doubt it would even be close ...

But it seems the overwhelming response is to just weld it up an go ...

I guess we can put driveline shops right up there with automotive machine shops , balancing is just another money grab ...

not me..I have had it come out at 105 mph on I-75,it was out of balance/out of phase/home cut/weld..machine shop said it looked to have bent in the middle and then broke a u-joint/yoke weld.

speculating here,but seems thats what happend,vib from the git go and got worse at speed,let off and BANG!!

not to mention 2 mufflers,3 feet of exhast pipe,1 rear shock and one hell of a bang.

I will just keep my local shop in bizness,cuttin and balanceing my junk.

cant see puting 3-4-5 K into and engine and risk the balance on it myself,but then again i run used junk most of the time antways..but it does have the factory balance

do you feel lucky?..good luck with it?

seems a lot of guys get away with it,I did for a while,cost more in the long run though

Posted By: 73rrak

Re: Shortening a driveshaft yourself - 11/12/11 04:18 PM

They just did this on that muscle car show on the " Power Block " That's on Saturday morning last week. It looked pretty simple and it looked like it worked . Buuuuuuuut I did know a guy that lost the front U-joint on his Chevy pick up. The driveline fell out and stabbed the ground it pole vaulted the truck #ss over tea kettle and they found him between the top of the dash and the roof of the cab squashed flatter than a fart. I think I'll keep paying the $100 for a cut, balance and new U-joints. It's money well spent.

Posted By: John_Kunkel

Re: Shortening a driveshaft yourself - 11/12/11 10:26 PM

Quote:

thats kinda getting back to "getting away with it" no?

the tube end does need a nice straight cut to seat the yoke and help phase it I would think.

Nope, being square has nothing to do with phasing and the yoke doesn't need to be fully seated as long as the center-to-center distance is the same on both sides...a little gap will just be filled with weld anyway.

I have done numerous driveshafts at home, on some of them I bought brand new end yokes and drove them into tubing that had been squared off in my lathe and never had a problem. Later on I found that this doesn't quarantee centers are equidistant...using a vernier to check the center distance often leaves a slight gap on one side before welding.

Posted By: larrymopar360

Re: Shortening a driveshaft yourself - 11/12/11 10:37 PM

Quote:

I had a driveshaft shortened at a metal fab shop once. What you described is exactly what they did. I never had it ballanced and didn't have any problems. Obviously the proper way is to have it ballanced. I'm sure I just got lucky.

Ditto for me, twice.

Posted By: 6PakBee

Re: Shortening a driveshaft yourself - 11/12/11 10:56 PM

I've never had a driveshaft shortened but having Dodge trucks with driveshaft splines I've had more than one spline replaced. Always had them balanced. One time the shop screwed up the phasing and I got a fairly bad vibration from it. Took it back to the shop, they cut it open again, rewelded it, and life was good. No balance the second time through. My conclusion? Phasing is more important than balance.

Posted By: slantzilla

Re: Shortening a driveshaft yourself - 11/13/11 03:13 AM

For the record, the shaft in my Valiant was cut and rebalanced by a driveline shop.

However, I've seen a ton of Mopars (mostly 4 speeds) toss the factory driveshaft through the floor in the traps. That's right, all original Ma Mopar driveshafts will break too. The balance job on many of them was nothing to write home about when they were new.

Would I cut my own now? Sure. But, I also have access to a lathe and mig welder now.

Posted By: HEMIFRED

Re: Shortening a driveshaft yourself - 11/13/11 03:40 AM

Quote:

The reality is that most driveshaft tubing isn't all that round so dial indicating is useless and the method of separating the tubing end is irrelevant as long as the end is reinstalled in phase and equidistant with the other.

Ok in 1968 I built an altered wheelbase 62 plymouth.
I cut the driveshasft with a pipe cutter removed 15". To assemble it and have it be perfectly straight I decided to find something to fit inside or outside to use as a jig. I found that an old school grease can which was made of a cardboard body with metal top and bottom was nearly a press fit. I had scratched a line to phase the joints before cutting so with my third time ever turning on a machine the welding began. It worked perfect and I still laugh at not knowing it could not work.

Posted By: dartman366

Re: Shortening a driveshaft yourself - 11/13/11 03:51 AM

Quote:

Has anyone tried this driveshaft kit? I've been thinking of doing that for my small to big block conversion.

Driveshaft kit from Mancini's

That's the very same kit that has been in my race car since 1993 and has held up well,,,and yes it was balanced after it was cut to length and welded.

Posted By: Anonymous

Re: Shortening a driveshaft yourself - 11/13/11 03:55 AM

I have a local shop that shortens, balances, and puts in new spicer joints for under $140.00.

Turnaround is usually one working day.

I'm big on doing things myself but sometimes you just gotta hire the experts with the proper equipment.

Posted By: Supercuda

Re: Shortening a driveshaft yourself - 11/13/11 03:56 AM

I was watching the speed channel last weekend and I think it was Trucks! they had on where they cut a driveshaft with a sawzall and wire welded the yoke. Scary how they glossed over checking phasing or anything else.

Posted By: dartman366

Re: Shortening a driveshaft yourself - 11/13/11 04:02 AM

Quote:

squashed flatter than a fart.

I would love to know,, but do I dare ask?

Posted By: Finoke

Re: Shortening a driveshaft yourself - 11/15/11 04:42 AM

Quote:

Quote:

Has anyone tried this driveshaft kit? I've been thinking of doing that for my small to big block conversion.

Driveshaft kit from Mancini's

That's the very same kit that has been in my race car since 1993 and has held up well,,,and yes it was balanced after it was cut to length and welded.

that is good to hear. Thanks

Posted By: 4speeds4me

Re: Shortening a driveshaft yourself - 11/16/11 05:51 AM

I've done quite a few myself with never an issue. That said, if I had a vibration or something didn't feel or look right, I wouldn't hesitate to have it gone over. If it's phased correctly and you've verified that the yoke is square in there, there is no reason you can weld it as well as a shop (assuming you have reasonable skill in that department). Therefore the only thing you aren't equipped to do is balance, and if it's that far out, you'll take care of that anyways.

My

...

Posted By: bboogieart

Re: Shortening a driveshaft yourself - 11/16/11 03:03 PM

Quote:

I was watching the speed channel last weekend and I think it was Trucks! they had on where they cut a driveshaft with a sawzall and wire welded the yoke. Scary how they glossed over checking phasing or anything else.

This is because these shows are hour long comercials and not intended to actually show you how things should be done right. Seems to me they spend more time telling how good the parts they used were.

As for drive shafts. I had one built by an implement shop. Asked the guy to ballance it. His response was it won't need it, as the new tube did not have a seem. Don't know about a seam in the stock shafts ( never saw one) but this one started to vibrate and got worse. I went to the junk yard and got the right one for my swap. (904 to 727) I don't listen to shop help any more and I find out what I need to know befor having anybody touch my stuff. I once had a mechanic tell me he wouldn't swap my gears in an old truck rear . I had another one I wanted to use for better mileage. His response was he could not do it cause one was posi and one was sure grip. I told him to go f&#% himself.

Posted By: DAYCLONA

Re: Shortening a driveshaft yourself - 11/16/11 06:20 PM

Unless you possess the skill and equipment to assemble/weld and balance a shaft, send it out

, whats $100-$400 to have a shaft made/shorten/etc....

keep in mind "most" driveshaft shops are set up for the average Joe's daily driver, meaning their equipment for balancing is usually limited to 3500 RPM shaft speeds,...a performance oriented shop usually has equipment that takes a shaft up to 10,000 RPM, something to consider on a high RPM running car, or one equipped with an OD in the .64 to .50 range, prop speeds can get up there in the RPM range

Posted By: Pyper70

Re: Shortening a driveshaft yourself - 11/16/11 09:06 PM

Didn't read the whole thing, maybe someone else said it...but for $100 bucks done correct by someone who does them all day along is money well spent. Imagine doing it yourself and then getting a stress fracture which circles around the whole driveshaft. If its the front yoke...how would you feel about catapulting your car on a public road, injuring yourself, other driver, or your car?

Posted By: JohnRR

Re: Shortening a driveshaft yourself - 11/16/11 09:33 PM

Quote:

how would you feel about catapulting your car on a public road, injuring yourself, other driver, or your car?

That's what insurance is for ...

Posted By: John_Kunkel

Re: Shortening a driveshaft yourself - 11/17/11 12:09 AM

Quote:

Imagine doing it yourself and then getting a stress fracture which circles around the whole driveshaft.

Imagine changing your own oil and leaving the drain plug loose.

Like the Clint said in the movie, "a man's gotta know his limitations".

Posted By: Pyper70

Re: Shortening a driveshaft yourself - 11/17/11 12:19 AM

Quote:

Quote:

Imagine doing it yourself and then getting a stress fracture which circles around the whole driveshaft.

Imagine changing your own oil and leaving the drain plug loose.

Like the Clint said in the movie, "a man's gotta know his limitations".

You are comparing something that you do once maybe twice during the life of a car and something you should be doing monthly. If you can't tighten an oil pan bolt I hope you can see the stream of oil running down your driveway before you drive 2000 miles and have a booboo

Posted By: Pyper70

Re: Shortening a driveshaft yourself - 11/17/11 12:21 AM

Quote:

Quote:

how would you feel about catapulting your car on a public road, injuring yourself, other driver, or your car?

That's what insurance is for ...

The point is to not require insurance for something that could be accomplished for $100. The deductible you are going to pay for the insurance is probably 5x the price of sending the driveshaft out and a whole lot less of a headache later on

Posted By: JohnRR

Re: Shortening a driveshaft yourself - 11/17/11 02:10 AM

Quote:

Quote:

Quote:

how would you feel about catapulting your car on a public road, injuring yourself, other driver, or your car?

That's what insurance is for ...

The point is to not require insurance for something that could be accomplished for $100. The deductible you are going to pay for the insurance is probably 5x the price of sending the driveshaft out and a whole lot less of a headache later on

I left out the

... sorry ... it was a joke .

Posted By: Anonymous

Re: Shortening a driveshaft yourself - 11/17/11 03:59 AM

Quote:

Quote:

Quote:

Quote:

how would you feel about catapulting your car on a public road, injuring yourself, other driver, or your car?

That's what insurance is for ...

The point is to not require insurance for something that could be accomplished for $100. The deductible you are going to pay for the insurance is probably 5x the price of sending the driveshaft out and a whole lot less of a headache later on

I left out the ... sorry ... it was a joke .

Lawyers, too, you left out Lawyers...

Posted By: Pool Fixer

Re: Shortening a driveshaft yourself - 11/17/11 05:52 AM

Quote:

Quote:

squashed flatter than a fart.

I would love to know,, but do I dare ask?

Not what I want on my tombstone. I live where everything costs out the Azz and everyone has their hand in your pocket for something. I used the mancini kit, mocked up in car, drew a line with a sharpie where I wanted them to cut and took it to the shop. It was like 50 or 60 bucks.

Posted By: Pyper70

Re: Shortening a driveshaft yourself - 11/17/11 09:54 AM

Quote:

Quote:

Quote:

Quote:

how would you feel about catapulting your car on a public road, injuring yourself, other driver, or your car?

That's what insurance is for ...

The point is to not require insurance for something that could be accomplished for $100. The deductible you are going to pay for the insurance is probably 5x the price of sending the driveshaft out and a whole lot less of a headache later on

I left out the ... sorry ... it was a joke .

That smiley changes everything

Posted By: John_Kunkel

Re: Shortening a driveshaft yourself - 11/17/11 07:50 PM

Quote:

You are comparing something that you do once maybe twice during the life of a car and something you should be doing monthly.

The point is, some people have the capabilities no matter how often they do it and some don't. Doing a driveshaft yourself is no different than building a motor (which one might do only every few years) if you know how to do it correctly.

People have been "backyarding" driveshafts since the beginning of hotrodding.

Posted By: Pyper70

Re: Shortening a driveshaft yourself - 11/17/11 09:50 PM

Quote:

Quote:

You are comparing something that you do once maybe twice during the life of a car and something you should be doing monthly.

The point is, some people have the capabilities no matter how often they do it and some don't. Doing a driveshaft yourself is no different than building a motor (which one might do only every few years) if you know how to do it correctly.

People have been "backyarding" driveshafts since the beginning of hotrodding.

Which I understand. But the OP is asking if what he will be doing will suffice and if he is missing anything. We can infer he has never done one before...when I built my first motor I didn't ask a whole bunch of questions...I just did it by a book...and it worked. Even the most knowledgeable welders will still take it to a driveshaft shop because weld is one thing...the balance is not.

We all give our "in favor of" and "against the job" for various things. If the OP'er (and no offense to him) was sure about doing it...he wouldn't have asked.