Need New C-Joint, Or Did He Say U-Joint

[texasz]

Ok, I swung by the Z-Clinic this morning and the owner/mechanic told me that the awful noise coming from the passenger rear was a very bad c-joint. He wants $125 for the one side and stated that the part is about $50 from the dealership.

I was looking in both VB and MSA catalogs and did not find them...did I misunderstand and he said U-Joints? Is there such a thing as a c-joint?

So if it is the u-joint then they run $12.95/each from VB for the stock type and $17.95/each for the same at MSA. Now MSA also has a Spicer heavy duty u-joint they recommend for racing which costs $32.95/each. Does anyone know how much better these are? I will be autoxing my Z and would like to know if the extra money is worth it on these.

Other questions are how hard of a job is this? Do I have to replace ALL the u-joints at the same time or not? If yes does this include the ones on the drive shaft or just the half shafts?

[hmsports]

He probably meant a CV joint -- which Zs do not have.

I have used the same set of Spicers for years of hard racing (over 50 race days) and didn't break one until my cart-wheel acceident where the whole suspension was ripped out. I would highly recommend them.

[St.stephen]

The U joints aren't that hard to do. You need plenty of penetrating fluid, a screwdriver, and I would suggest a mallet. You have to get the C clips off the ends and then knock one side out and remove the cups with the needle bearings. Be sure to mark the yolks so that you can match them together as they were. make sure also that you get greasable U joints (they will have Zerk fittings on them) so you can properly lube them. Also, it might not be a bad idea to bring the halfshafts to a drive shaft place and have them checked to ensure they are properly balanced.

I don't necessarily think that you have to do the driveshaft as well, however if you are going through the trouble to do the halfshafts, why not do them all. Nothing worse then doing kind of the same job twice, when you can just do it all at once and know that you won;t have to be under there doing it all over again.

[hmsports]

Remember to wear safety glasses when you pull the C-clips off as they have a tendecy to fling off at a high rate of speed.

[texasz]

He must have said U-Joint and by the time I posted this I was just confused (he's very knowledgable about Z's, he has been working on them since the beginning and went to the first Z school that Datsun/Nissan held).

The question I have before ordering them is since all he did was drive the car and not put it in the air how can I tell if this it the real problem? Can I just jack the car up, roll under there, look at them and be able to tell? What will I be looking for to tell if this is the problem? I just don't want to order the expensive u-joints from MSA and find out that this was not the problem after all.

While I'm there how much more work is it to swap the diff? I have my new one sitting in the garage ready to go!

[kmack]

The easiest way to check for wear in U-joints, is to jack up the car and, with the car in gear and parking brake on, try to rotate the half-shafts or drive shaft (which ever one you want to check). Keep in mind there will be some play due to tolerances in the diff., but what you are looking for is play or movement at the u-joints (one side moving while the other side isn't).

With regard to Spicer U-joints, if you plan to do even some high-spirited street driving, get these! These are the same brand that all the semi trucks use and for two reasons: they hold up to large power demands and they last.

[texasz]

kmack, great info! I will be doing that in the next day or two.

About my other question...how much more effort would it be to swap the diff while I'm doing the u-joints? I'll be under the car, I'll have the shafts partly taken apart already...

[Mike]

This is one of my 'do it right or do it again' words of wisdom. I have a '71 and learnt the hard way. First time, I removed all shafts and pulled out the ujoints myself. Purchased cheap replacements and put them in myself. Had to replace those again in a year. So, I paid someone to do it the 2nd time. But, purchased cheap joints. Another couple years... did it again. This time, I had someone install them and I purchased stock ujoints (paid the price).

So, go get GOOD u-joints and pull the shafts yourself. Take the shafts down to a local shop and let them press 'em in.

[abas]

texasz

changing the diff is pretty straightforward bolt in affair. I found it a bit awkward to do it on my own especially if you can only lift the car a short way on axle stands.

Best way is to

1) jack back of car up and put on axle stands

2) place trolly jack under rear of diff

3) remove half shafts and drive shaft

4) release the back of the original diff at the 2 outside moustache bar nuts.

4) Undo do the 4 bolts holding in the front diff cross memeber to the floorpan

lowering the trolley jack, the diff *should* lower with it.

(I can't at present remember whether the rear suspension a-frames will foul the diff as you lower it, if the do it is a simple matter of removing the rear a-arm cross member. You will know what I mean when you are there!!!

5) swap the moustache bar and front cross member over to new diff. Check your front diff mount and outer mostache bar bushes for deterioration while it is out.

6) check the diff strap that is left on the car above where the diff goes for wear deterioration.

7) and as it says in the Haynes manual 'replacement is a reversal of the above :classic:

Are you going to change the speedo drive gear. I presume you speedo will be out once you change the diff.

hope it helps

Andrew

[baddriver]

I've changed U-joints in a number of cars before, but the Z joints are tight! I could not get them apart for anything. Took them to a shop that had a press, and they got them apart for $20.

If you are going to do them yourself, I highly suggest you get a u-joint press or arbor press to do it with. A press is around $50 to $100, but if you are going to do all four half-shaft joints, a shop will want at least that much.

Spicer are good joints, but there is nothing wrong with the Brute-force joints either. I used these, and they are every bit as solid as the Spicer joints, plus my local auto place had them the next day.

[1975yellowBSPZ]

Hey TexasZ, we always seem to meet like this...

Have you had the chance to replace your u-joints? I am suspecting I may need to do the same and want to know how it went. I swapped in my spare motor over the weekend, It was pretty str8 forward. I have not reinstalled the FI etc as I have a sheared exaust stud and subsiquent sheered easeout to deal with... Looks like I'm just going to have a head job on my old head and kill 2 birds with one stone rather then worry with trying to drill that easeout out of there, so It'll be a while before I get everything back together. I'll let you know how everything goes. And I need some radiator work too....

[texasz]

1975yellowBSPZ, I have not done the job yet. I have ordered the Spicer joints only for the side that is bac (2 joints) and will let you know how it goes after I have done it. I would like to have a go at it this weekend if the parts come in time.