U joint. How much play is acceptable?
 

Whilst the transmission is out I'm checking the U joint. It has done at least 20K miles no problems - greased regularly . All looks good but I estimate it has about 2 thou play- ie just detectable. Is this aceptable ? Should I leave well alone or buy a rebuild kit ?

Re: U joint. How much play is acceptable?
 

Being that the u joint is not readily accessible i would go ahead and rebuild it for peace of mind.

Re: U joint. How much play is acceptable?
 

The new old stock parts have play in that range, most likely modern reproduction parts will fit worse

Re: U joint. How much play is acceptable?
 

I expressed a concern with my 2011 Ford Ranger Truck now nine years old. You engage the automatic transmission and you can hear a distinct "thunk" as the loose motion is taken up and torque is transmitted to the rear end.

I asked the mechanic about this - was it of concern and should I plan on a replacement?

"Yes you should plan on a replacement, but it might occur a week from now or it might go the remaining life of the truck" (it had 75K at the time of the question.")

"Were it my truck, I would leave it for the day when you get the "clunk" but you get no go - meaning the U-joint is failed and the yoke is spinning without any clevis to transmit the force."

A previous Chevrolet C1500 I owned in the 90s had a similar issue, but this being a manual transmission (unusual in that day and age and vehicle) At that time the mechanic had some of the same sort of advice, but with a caveat: "If you feel a change and detect an usual vibration, that means that the universal is hanging up and not 'universalling.' I would have the universal replaced if you detect that and it has not failed completely."

So unless you have either of these I would go with it - unless you for the pleasure and peace of mind feel compelled to replace it.

As I understand it, universals almost universally (heh) are made by Dana-Spicer in the US. Model A universal especially. Production of the Model A universal is spotty - D-S will make a bunch, sell a bunch, and then sit back and wait for demand to re-emerge before raising the price and producing another round of production. So if you seek a universal, you may find difficulty in getting same - particularly now in today's post-Covid world.

Mostly the market has anticipated that. Model A parts houses almost always have sufficient stock to "ride out" the low spots in D-S production - but not always.

And many prefer "new old stock" of the original universals in the later clevis & yoke style. The earlier ring & yokes are still found and many are still working, but it's been out of production since about 1930 and most are now worn out.

Joe K

Re: U joint. How much play is acceptable?
 

Any rotational play that can be dealt is too much. But side to side sliding play is normal.

Usually any 'clunking' when changing gears such as park to reverse or reverse to forward in an automatic transmitter is in the rear yoke and not the u-joint. This can happen in a manual also but usually is not felt as much.

Re: U joint. How much play is acceptable?
 

About 12 months ago, I refitted a joint with about 1/32" rotational play at the tunnion. I've seen cars going just fine with waaay more than that too. The idea of replacing mine never even occurred to me.
Years ago, I had one with more than 1/8" slop there. I took that one apart and fixed it but obviously, it was still going the day before it was taken out when the car was dismantled.

Re: U joint. How much play is acceptable?
 

Quality is the big issue in locating a new U Joint. I bought a new unit from one of the regular parts houses and was disappointed. It had more play than your used U Joint and the spline was off center. I did not use it and eventually located an excellent NOS unit probably made back in the 60s. If you can find a good one it is probably worth changing since everything is already apart.

Re: U joint. How much play is acceptable?
 

I am assuming the play you have found is when the the U/J is "dry" and has been washed out with solvent if this is the case that U/J is good to go for many more thousands of miles in my view . If it is well packed with grease on reassembly it will see you out for sure . When you buy rebuild kits are the parts genuine Spicer even if in a Spicer/Dana box ??? You could be lucky and find a NOS unit but I think you would be lucky if you did .

John in sunny morning (yes really !!!) Suffolk County England .

Re: U joint. How much play is acceptable?
 

There are 2 u-joints used in the Model "A". The original u-joint (1st photo) was riveted together and not rebuildable. The riveted u-joint should not be used. The replacement u-joint (2nd photo) is a conventional design that can be rebuilt. Regarding the replacement u-joint, it has slip fit bearings, so there will be a few thousandths of rotational play. Assuming that each of the 4 bearings has a 0.001" slip fit, then at least 0.004" minimum rotational play is reasonable. The maximum rotational play is ?????.

Re: U joint. How much play is acceptable?
 

Thanks everyone. I have one of each type of U joints in the garage .... Possibly surprisingly the riveted one ( which I assume is older) has no discernable play at all .... whilst the replacement type is the one i was wondering about using after maybe fitting a rebuild kit.

Re: U joint. How much play is acceptable?
 

Might want to check with Steve at Berts before you invest in rebuild kit. He has indicated before the quality of the rebuild kits are not acceptable, believe he stopped selling them. Maybe he will chime in.

You can get a u-joint from Drakes that has needle brgs.

https://www.bobdrake.com/FordItem.aspx?Item=HB-7090