Balancing front prop. shaft.

[discomuzz]

Hi folks.

I have replaced the Uni's. in the front prop. shaft.

Like a goose, I didn't mark which components were up, down, this way or that.

I now have a slight vibration under certain conditions.

I am thinking, I either have an unbalanced prop. shaft or the Uni problem was only an indicator to a larger problem (260,000 ks).

Any thoughts?

[djam1]

Did you assemble the shaft out of Phase??
Thats the way it was when it was manufactured

[discomuzz]

Did you assemble the shaft out of Phase??
Thats the way it was when it was manufactured

Quite probably!

I made sure that the yolk on the driveshaft was 180 degrees out from one end to the other when I put it together.

[JDNSW]

The sliding joint should have marks each side to show how it should be assembled. You may need to clean it up to see them. The ones I have seen are an engraved arrow on each part, which should be assembled pointing to each other.

John

[discomuzz]

The sliding joint should have marks each side to show how it should be assembled. You may need to clean it up to see them. The ones I have seen are an engraved arrow on each part, which should be assembled pointing to each other.

John

That's what it says in the Haynes manual!

But, for the life of me I couldn't find any identifying marks.

I just had to consider rotation and try to balance the thing by sight, so to speak(i.e. grease nipples opposite, yolks opposite, etc...)

Are you suggesting I pull the whole thing out and have another look?

I don't mind! I want it to work. But...?

[discomuzz]

Bump... Anyone please?

[mike 90 RR]

Bump... Anyone please?


This is a brand new front propshaft from the RRC 1990
I "think" the "out of phase" for this model is "29 degrees"

The problem with yours is it is out of balance as you have lost the spline markings .... and just changing the uni joints is enough also to throw it out of balance ..... hence "have lost the balance of the shaft"

Have a look at mine

12180

You might as well spend the $100 and get it done properly ... as a unbalanced shaft will cost you on diff & transfer box seals & bearings

Hope it helps

[rovercare]

Getting perfectly good hsafts balanced is a load of crap, they don;t go out of balance unless something changes, either you've incorrectly fitted the uni's or the worng ones, or most likely the phasing of the prop is out,

1. fit it together so both the inside the flanges are "in phase", then pull it apart and turn it "out of phase" 1 spline and refit

2. promptly report back here, preferably with pics:D

[mike 90 RR]

they don;t go out of balance unless something changes, either you've incorrectly fitted the uni's or the worng ones, or most likely the phasing of the prop is out,

1. fit it together so both the inside the flanges are "in phase", then pull it apart and turn it "out of phase" 1 spline and refit


I made sure that the yolk on the driveshaft was 180 degrees out from one end to the other when I put it together.

Now there's the hint of the problem :p

But he has lost the "line up marks" :(




Getting perfectly good hsafts balanced is a load of crap, they don;t go out of balance unless something changes, either you've incorrectly fitted the uni's or the worng ones, or most likely the phasing of the prop is out,

Propshafts would be "naturaly balanced" except for the welding and the way they are constructed .... As they are not "true" for being straight ... most of them have a slight bend in them ... from being welded // ect

My thoughts anyway ;)

[rovercare]

Propshafts would be "naturaly balanced" except for the welding and the way they are constructed .... As they are not "true" for being straight ... most of them have a slight bend in them ... from being welded // ect

My thoughts anyway ;)

That's why they are balanced from factory, but unless the wieght drops of or something changes, a dent etc, then there is no need to rebalance

I've got quite a few shafts made by my mate, all statically balanced, not dynamic and all work well:D

[mike 90 RR]

That's why they are balanced from factory, but unless the wieght drops of or something changes, a dent etc, then there is no need to rebalance

I've got quite a few shafts made by my mate, all statically balanced, not dynamic and all work well:D

I know of a "well respected" mechanical engineer who puts in the time to make the shaft straight (Not bent) ... heats up the shaft and straightens it out on the lathe .... No weights required

Your right on the balance subject tho :)

The only way a shaft can unbalance itself is under extreme loads where it makes the shaft twist heavily and kinks the pipe further // Examples would be "Burn out Kings" or the towing of heavy caravans

I'm just fussy, and did go "just a little" over board with a "New Shaft"


The only reason i'm suggesting that he gets it balanced is because he could have up to (worst case senario) "8 positions??" to try ... to get it right :( as he lost the original markings


:)

[rovercare]

I know of a "well respected" mechanical engineer who puts in the time to make the shaft straight (Not bent) ... heats up the shaft and straightens it out on the lathe .... No weights required

Your right on the balance subject tho :)

The only way a shaft can unbalance itself is under extreme loads where it makes the shaft twist heavily and kinks the pipe further // Examples would be "Burn out Kings" or the towing of heavy caravans

I'm just fussy, and did go "just a little" over board with a "New Shaft"


The only reason i'm suggesting that he gets it balanced is because he could have up to (worst case senario) "8 positions??" to try ... to get it right :( as he lost the original markings


:)

Rotating through all 8 positions is better than spending the money getting a shaft balanced:D

How does he heat it up and straighten it on a lathe?

All the ones we've done have been largely spigoted, useing a yoke that fits in the gearbag to fit in the shaft as the locator with a sleeve if necessary, machined to neat fit, then I just phase it and weld it up, simple and effective and I've have a few well over the double metric ton with no vibes:)

[mike 90 RR]

How does he heat it up and straighten it on a lathe?

Build new propshaft ....

Put shaft in lathe ... turn ... look for bend ... warm it up ... Turn & roll it out

Takes time ... and i'm speaking in general terms



All the ones we've done have been largely spigoted, useing a yoke that fits in the gearbag to fit in the shaft as the locator with a sleeve if necessary, machined to neat fit, then I just phase it and weld it up, simple and effective and I've have a few well over the double metric ton with no vibes:)

If that works for you .... wouldn't change the method for quids :) .. All thumbs up ... :) cause its "all in the eye" :)


Even that new one I have, is slightly bent in the middle (from a weld line in the center) ... so it has a dag weld + a weight in the center of the propshaft .. Mongrel design ;) .... (The shaft was rebuilt by others ... not the engineer I mentioned)

[leeds]

When I had my rear prop shaft repaired in Darwin by transmission specialist they stated that ALL prop shafts should be rebalanced when new UJs fitted

Regards

Brendan

[rovercare]

Build new propshaft ....

Put shaft in lathe ... turn ... look for bend ... warm it up ... Turn & roll it out

Takes time ... and i'm speaking in general terms




Wouldn;t that cause alot of hardening to the steel used?, he'd have to get it cherry red, unless he's set up a stress roller of some kind on the bed?

[rovercare]

When I had my rear prop shaft repaired in Darwin by transmission specialist they stated that ALL prop shafts should be rebalanced when new UJs fitted

Regards

Brendan

Should rotate your tyres every 5k and balance them every 10k to:D

[mike 90 RR]

Wouldn;t that cause alot of hardening to the steel used?, he'd have to get it cherry red, unless he's set up a stress roller of some kind on the bed?

He has the tools ... and is old school taught
That's why he's the "engineer" and I'm just the "layman" .... :(

[rovercare]

He has the tools ... and is old school taught
That's why he's the "engineer" and I'm just the "layman" .... :(

I just wanna know how he does it, I'm curious thats all, spill the beans?

[mike 90 RR]

I just wanna know how he does it, I'm curious thats all, spill the beans?

I've gone as far as I can in the method


You would have to ask him yourself .... as for asking about subjects of hardening & softening of the metals // etc ....... I can't answer that, as I would be talking out of my ... well you get the last bit :p


There are some other engineers here who could maybe expand on this method tho :)

[discomuzz]

That's why they are balanced from factory, but unless the wieght drops of or something changes, a dent etc, then there is no need to rebalance

I've got quite a few shafts made by my mate, all statically balanced, not dynamic and all work well:D


Mine has a fairly sizable dent in it!

Bugger it, Mr. Rudd's xmas bonus has found a new home by the looks of it.

I'll get it balanced as soon as I can work out the correct spline setup.

Thanks all.

[rovercare]

Mine has a fairly sizable dent in it!

Bugger it, Mr. Rudd's xmas bonus has found a new home by the looks of it.

I'll get it balanced as soon as I can work out the correct spline setup.

Thanks all.

If it has a dent, bin it, its just lost half its strength;)

[discomuzz]

If it has a dent, bin it, its just lost half its strength;)

Yeah, it's starting to dawn on me that this may be the case. Never thought about 'til now.

Might recover my new UJs though.

[mike 90 RR]

If it has a dent, bin it, its just lost half its strength;)


Eh .... Left that part out now .... didn't he :(


He can salvage it (if the cost is relevant) ... if the tube is cut out and replaced
Take it to a driveline shop and get it rebuilt .... should cost $350

or buy a second hand unit .... cheaper

Either way the shaft is knackered :(

[discomuzz]

So my local LR (non Stealership) dude tells me that I can drive this thing without the front shaft in if I put it in Difflock.

True or false?

And, If true, what timeframe can this be continued for?

Edit: It's OK. Did a forum search on the subject and looks like I can get away with no front prop. shaft for a while.

[rovercare]

Yeah, it's starting to dawn on me that this may be the case. Never thought about 'til now.

Might recover my new UJs though.

Good luck with that:o:p

[rovercare]

Eh .... Left that part out now .... didn't he :(


He can salvage it (if the cost is relevant) ... if the tube is cut out and replaced
Take it to a driveline shop and get it rebuilt .... should cost $350

or buy a second hand unit .... cheaper

Either way the shaft is knackered :(

You love spending money:D

[mike 90 RR]

You love spending money:D


Not really .... :(

... This thread is someone else's money :) .... So I don't mind spending theirs :angel: