Alfa Romeo Owners Club of Australia Forum

Technical => 932 Series (156, GTV, Spider, 147, GT, and 166) => Topic started by: Kay_147_GTA on April 02, 2019, 02:35:52 PM

Title: 147 GTA CV Joint Split Inner Boot
Post by: Kay_147_GTA on April 02, 2019, 02:35:52 PM
Hi All

So I've recently noticed that the inner boot on my drivers side CV joint has split and flung grease everywhere. I've found a handy instructional on Alfa Workshop on how to replace it which seems pretty straightforward, however I read somewhere that removing the CV joint from the gearbox will cause the transmission fluid to empty out of the gearbox. This isn't mentioned in the instructional so just wondering if anyone has done this before and should I empty transmission fluid first?

Thanks
Title: Re: 147 GTA CV Joint Split Inner Boot
Post by: bazzbazz on April 02, 2019, 02:54:54 PM
That is incorrect. You are only removing the outer drive shaft, not the output half shaft. No need to empty oil.

Which guide are you using? Post a link.
Title: Re: 147 GTA CV Joint Split Inner Boot
Post by: Kay_147_GTA on April 02, 2019, 03:01:22 PM
Sorry should have posted

http://www.alfaworkshop.co.uk/GTV_Spider_Inner_CV_boot_replacement.shtml
Title: Re: 147 GTA CV Joint Split Inner Boot
Post by: bazzbazz on April 02, 2019, 06:13:10 PM
No, you don't.

Go read the link, though it is for the GTV it is basically the same for the 147 as well.

Title: Re: 147 GTA CV Joint Split Inner Boot
Post by: Kay_147_GTA on April 02, 2019, 08:29:48 PM
Cool, thanks guys
Title: Re: 147 GTA CV Joint Split Inner Boot
Post by: bazzbazz on April 02, 2019, 08:32:33 PM
You will find it MUCH easier to remove the whole driveshaft and do the boot replacement on the workbench. TRUST ME!
Title: Re: 147 GTA CV Joint Split Inner Boot
Post by: Citroƫnbender on April 02, 2019, 10:46:35 PM
Quote from: bazzbazzYou will find it MUCH easier to remove the whole driveshaft and do the boot replacement on the workbench. TRUST ME!
You meant to say "Exchange the shaft for one rebuilt on the bench, in advance"?  :)

Either way, one needs a Ligarex tool or crimping pliers depending on how it may be strapped...
Title: Re: 147 GTA CV Joint Split Inner Boot
Post by: johnl on April 03, 2019, 08:06:04 AM
Quote from: Citroƫnbender on April 02, 2019, 10:46:35 PM
Either way, one needs a Ligarex tool or crimping pliers depending on how it may be strapped...

I've always replaced the original straps with large pull ties, which have never given a problem, work perfectly, and are much easier to fit (and remove).

Regards,
John.
Title: Re: 147 GTA CV Joint Split Inner Boot
Post by: bazzbazz on April 03, 2019, 11:17:54 AM
Unfortunately they do not provide enough tension to seal the boot against moisture, and can allow the ingress of water into the joint and cause corrosion. Sadly I have had more than one client suffer from this.
Title: Re: 147 GTA CV Joint Split Inner Boot
Post by: johnl on April 05, 2019, 08:59:45 AM
Quote from: bazzbazz on April 03, 2019, 11:17:54 AM
Unfortunately they do not provide enough tension to seal the boot against moisture, and can allow the ingress of water into the joint and cause corrosion. Sadly I have had more than one client suffer from this.

Can't say I've ever had such a problem, and I've been using pull-ties on CV and steering rack boots for years. I use big ones, and pull them very tight (I can see the boot rubber being squeezed / squashed under the tie, so that the rubber is 'extruded' laterally from beneath the tie). I can imagine problems if using smaller ties that can't be pulled tight enough before they break...

Regards,
John.
Title: Re: 147 GTA CV Joint Split Inner Boot
Post by: bazzbazz on April 05, 2019, 09:22:45 AM
At high revolution the Cable Tie expands, along with the rubber boot allowing the ingress of moisture. That's why they use metal bands, they don't stretch.
Title: Re: 147 GTA CV Joint Split Inner Boot
Post by: johnl on April 06, 2019, 07:04:14 PM
Quote from: bazzbazz on April 05, 2019, 09:22:45 AM
At high revolution the Cable Tie expands, along with the rubber boot allowing the ingress of moisture. That's why they use metal bands, they don't stretch.

Baz,
Sorry, but I just can't see this happening.

The pull / cable tie is very light, as is the boot being held in position by it (light as in not having much mass). The material from which the tie is made (nylon I assume) is tough and quite resistant to elastic stretching (within reason). For centrifugal force to cause the tie to stretch enough that a gap opens between the boot and joint / shaft would require the centrifugal force to be extremely high, as could only be caused by the shaft rotating at a very high rpm, and /or the distance from the axis of rotation to be quite substantial.

None of these things are the case. I don't know the ratios etc, but I'd be amazed if the shaft speed ever approached 2000 rpm (for example a 4.1 diff ratio would give only 1,700 shaft rpm at 7000 engine rpm, with a 1/1 gear ratio, assuming the power to reach such rpm, i.e. road speed). So, the maximum shaft RPM is relatively modest, and the distance of the tie from the centre of rotation relatively small. The centrifugal force acting on the tie and the boot will therefore not be nearly great enough to create a gap between the boot and the joint or shaft.

I could be wrong, but I'd be very surpised...

Regards,
John.
Title: Re: 147 GTA CV Joint Split Inner Boot
Post by: Mick A on April 06, 2019, 09:07:04 PM
What you say makes a lot of sense, and it is true driveshafts don't actually rotate as fast as one would think.

I've used cable ties on my race car driveshafts for many years with no problems. Never had a drop of grease escape.

However, the only issue I've ever found is on front wheel drive shafts, if you use them on the outer boots, when the wheels are turned the cable tie's locking tab can rub against the boot, eventually causing it to tear prematurely, or the cable tie to break, making a big old mess.

Mick.
Title: Re: 147 GTA CV Joint Split Inner Boot
Post by: Kay_147_GTA on May 30, 2019, 10:21:37 AM
So ended up doing this with my front suspension, was a lot easier to get at with suspension off however it's a right PITA to get the 6 drive shaft nuts back on the back of the knuckle, definitely need small hands!

Also beware, I bought a CV boot kit which contained 4 identical boots, these turned out to be correct for the outers but the inners were different, so had to go chasing down the correct inner one mid-change.