Inner CV to Drive Flange Bolts

I need to do the inner CV boot on my mk1 GTi. I started to take the driveshaft off and have found that either the inner cv to drive flange bolts are WAY overtightened by the previous owner/mechanic or they have been loctited. I've stopped for tonight as I'm concerned that I'm going to round them off.

Does anyone have any good tips for getting tight/knackered ones out?
I'm guessing I'm going to have to heat them with oxy-acetelene but I'm not sure I'll get enough heat in.

It's on the nearside/short driveshaft (not that it makes any difference!).

If they do round off, what do you have to do? Cut the driveshaft and take the gearbox out?

Are they the splined original ones, or have they been replaced with something else?

It looks like they are Allan key bolts, should they be 5 or 7 point splines?

Well mine had 12 point splined fittings, very fine. You need a descent splined bit to remove them, but you can put quite a lot of force through the splined bits when they are pushed home properly without it rounding off. However, a lot of people change these to Allan bolts when they change the CV boots etc. because they perceive them as easier to undo, although the reverse is true as allan bolts are much more likely to round off (in my experience) I've just rounded one off on my crankshaft pulley and that was with a well fitting bit as well.

If you still had the splined fittings, I was going to suggest making sure you had a good fitting bit that was properly driven home, then you should be OK with quite a lot of force, however if they are Allen bolts it's going to be a bit more tricky. Sometimes if the fitting is lose you can get away with using the next size up in a TORX fitting and hammering it into the end of the bolt to get a tight fit - however it's a one chance only affair that doesn't always work (but has in the past for me) I don't necessarily recommend trying it unless you've run out of other options.

Mike.

Yes, I've done that kind of thing before too, as you say though it's a one shot go and I don't really know what to do if it doesn't work, presumably it's a box out job?

I had this with one of mine. I got it off by drilling a hole (5mm) through the side of the bolt head and using a 4mm allen key slide through the hole to undo it. Bit of a pain on one, but a major task if you have to do all of them. I'd be more inclined to just grind off the heads and replace them. then you can take the cups off and work on the bench.
Good luck..

You can get special sockets which can 'grip' the outside of the bolt. However, because of the restricted space around the bolts I'm not sure these would be any good for those, I'm also not sure if they would grip well enough to remove something that tight.

As you can get to the edges of the bolts, you might be able to grind a flat surface onto two opposing sides and then get a good quality (so no flex) tight fitting spanner onto the bolt. Once you've cracked the thread they will undo fine, and replacement bolts often come with the CV boot kits.

And yes failing that, as above, grind the whole bolt head off, as the stubby bits should be easy to remove once there's no tension on them.

Use an impact driver and a hammer - it drives the bit deep and turns at the same time - never fails !!

If all else fails and I have to grind them off how does the cup attach to the box?
Is it a nut in the centre or do you need to strip the box to remove it?

Thanks

Simon

Held on by the bolts that you have just cut the head off.

You will have to undo the hub nut (very tight), undo and release the wishbone balljoint, pull the hub out so that you have enough room to pull the drive shaft out of the hub and then you will be able to pull it off the gearbox.

Then use some mole grips to turn the shaft of the bolt to remove it.

Sorry, I didn't mean the cup, meant the drive flange, although after searching I found a parts diagram that shows there is a circlip in the centre that holds it on, then it should pull off the gearbox output shaft.

OK. All came out with a bit of persuasion and care. Inner CV boot is now changed and they are replaced with new splined bolts and torqued to the correct torque.

Another piece of poor mechanics fixed, happy days!

Thanks for the advice guys.

Simon