Forester Front CV Shaft Replacement

[Zannu]

Hi all

Been enjoying my forester but recently noticed a vibration. It only happens when accelerating (first noticed on hard acceleration) and from about 40mph. From what I have read here and on other forums, this is likely to be the front inner CV joints. Over the Christmas break I did a tyre rotation, partly to check there wasn't anything with the wheels that could be causing the vibration and partly because I try to every once in a while. Whilst the wheels were off I tried moving the drive shafts, and the front left had 1mm or so play up, down, left and right at the gearbox end, so I believe this is my problem. I will replace both front joints whilst doing it. I already changed all the CV boots not too long ago, so thinking either I did something wrong then that has LED to the damage, or just 147K driveshafts are worn out, but I know what I am doing to be able to swap the parts myself.

So my question to you all - What is the best way to replace the front inner CV joints?

I read somewhere, think it was this forum, that all the knock off shafts are not worth having, better to replace just the joint. I am happy to do this, and probably the cheaper option. So what brand is best for the inner joints? Should I be changing the whole shaft seeing as I am there? (I want to keep the car for at least a few more years so worth doing it properly) When I pull the gearbox side of the joint out the box will gearbox oil pour out and so I need to have replacement fluid ready? Can I tell if I have 21 spline or 25 spline gearbox outdrives without pulling them out?

Any other advice from people who have done this job would be greatly appreciated.

Many thanks everyone,

Matthew

[Judd]

Before you splash out, have you repacked all 4 joints with fresh grease?

To make life easier, Laser make a grease gun adaptor, which is a long thin nozzle like a 3mm bore pencil, this connects onto your grease gun (i keep one solely for repacking CV joints) so you can just cut the narrow end clamp of each boot, feed the adaptor under the boot and up into the joint and pump some grease directly into the joint.

Can't recall the last CV joint ot drive shaft i've had to change, might have been on a Pug 306 in the 90's, i don't let them get to being worn but pump some grease into each joint every couple of years, usually at the same time i strip clean lube the brakes.

 

I haven't removed drive shafts from the Forester, but did renew the split inner joint boots on the previous Outback (they all do that sir), apart from the front hub being a really tight fit on one bearing the job was simple enough, the Outback joints were secured to the shafts by circlips, so once clips unsprung the whole joints could be slid off the shaft and taken apart for cleaning and regreasing, despite running for probably several months though a winter fully split by the previous owner there was no wear to be found in these joints, these are very well engineered cars, i hope the Foz shafts come off and apart as easily.

On the Outback the drive shafts didn't pull out of the box, the shafts were held to the output shafts by roll pins, usually with boxes you lose some oil removing standard shafts, but its a good opportunity to renew the front diff  and transmission oils whilst there, you never know repacking might see the existing joints have a new lease of life.

[Zannu]

Hi Judd,

Thank you for the reply.

I have not tried re-packing the joints, and didn't know about the laser tool for a grease gun. I thought that as mine was making noise it would probably be bad enough I would just need to replace it, plus I have driven on it for a while whilst it has been making the noise, but I shall try greasing them up.

I have also renewed the inner and outer boots on my forester, so I have had those circlips off before, and the joint taken off. I just wasn't sure how to get the gearbox side of the joint out. I shall have a look when I am next under my car.

 

I shall get all the items I need for greasing and have a go hopefully at the weekend. Thanks for the helpful comments and advice, I shall let everyone know how I get on and if re-greasing fixes my issue.

[Judd]

If you struggle to find that Laser adaptor, its in my garage and i keep it in the blister pack so the part number is available.

I'm not sure about how the drive shafts come out of the gearbox either, most cars it's a sprung circlip holding them in a slight groove so a suitable placed lever between joint and box provides enough pressure to pop the spring past its groove.

The roll pin design of earlier Outback was superb, just pop the roll pin out with a small hammer and suitable drift and the shaft just slid off the output spline, that should be how all shafts are attached, the roll pin wasn't taking any drive strain just keept the shaft from sliding along the splines, whoever designed that had future maintenance in mind not just cheap and cheerful manufacture.

Hope repacking those joints improves things for you.

[Zannu]

I have found a sealey one that looks like the type you are talking about, and bought a separate grease gun to use with CV grease. I have several already but they are being used for other greases. I think it will be worth having a dedicated one even if it isn't used that often (hopefully).

From what I can see/found online I think mine just have the sprung circlip, but if I can just re-grease that would be even better. I will check later but pretty certain I have some spare of the smaller diameter clips from when I changed the boots a while ago.

The roll pin design sounds super. Much easier than it leaking oil everywhere! I know on VW's and maybe more, they have a flange at the inner, so it just bolts together. Again, makes it easy to replace the joint.

[Zannu]

@Judd Thank you for the advice. This evening I have pumped lots of Morris Lubricants K48 Moly grease into my subaru's front CV joints. The vibration has gone, just as you said it might. I wasn't sure this was going to be my only issue, I was worried I had worn the joints to the point grease wouldn't do anything. Having been on a test drive it is so much better. I put some re-usable clips on the small end of the boot, that I don't like, but are easy to undo too. Maybe this weekend I will undo them and pump more grease in. It is odd just pumping away, there is no way to tell if grease is actually coming out apart from the resistance in the lever, and so I wasn't sure how much to do. Having been on a test I am sure it is the solution, so can go crazier. Seems like they were really pretty empty. I think the boot doesn't fit perfectly on the larger side of the boot as the outdrive is not circular and the boot is, so grease was escaping. Now I know this is the problem I have an idea to stop it leaking ever again.

Once again this forum saves me from lots of unnecessary wasted spending. Thank you

[Judd]

Well done Zannu, and thanks for letting us know it went, sorry for being late in replying only just seen the post.

I've found its always worth a try regreasing such things, used to prefer it when wheel bearings were simple taper affairs too, when you serviced the brakes it only took ten mins longer to loosen the bearing nut, and regrease the bearings, again kept greased they invariably lasted the life of the car as when we had greasable prop shafts and ball joints too, the only grease points left on my own cars are the two propshafts on my Landcruiser.

Purely out of interest, in my younger years of lorry driving lots of (especially British) wagons had autolube, this was a system with a central reserve tank filled with oil and dozens of pipes from this with the oil pumped at regular intervals to king pins, steering joints, spring shackles etc all around the vehicle, all of which joints as you would guess lasted years, some very upmarket cars i believe could have this system specified.

[Zannu]

Since my last post I have got what I believe to be the correct inner CV boots. I believe the lack of grease was caused by the boots being wrong, and so it all leaked out. I packed lots of grease into the joints, and re-assembled with the right boots and clips. So far everything seems to be good, no vibrations on the limited test drive I have been able to go on. Once lockdown is over I will be able to give it a proper test with some longer journeys just to check everything really is sorted once and for all.

Ah yes, I worked on Classic cars for a few summers not long ago and they were all very old style, with 2 opposed roller taper bearings to hold the hubs on, easy to re-grease or change when we had to. But these were on race cars so didn't have quite the life a road car would. Ashame that a lot of cars don't have easy to service components, we live in a replace age, rather than repair.

And interesting, I believe on steam engines they have an autolube system too, that keeps everything important coated with enough oil to ensure parts never wear out. A good idea on industrial vehicles that get a lot more miles piled onto them than a normal car.