405 Gearbox Rebuild and Clutch Change

evilally · Unread post by **evilally** » 28 Apr 2010, 22:01

I've been taking some advice from Jim on this, and he said I should start a thread about it as it might help others

My 405 is on 137k and has always crunched 3rd gear since I got it at 103k. This has really bugged me as I do a lot of b-road driving and I'm in and out of 3rd a lot. So when the clutch started to slip the other day, I thought I would just go for it and rebuild the box while I was doing the clutch. I've never touched a clutch or gearbox before, so I'll learn a lot here.

I picked up a box from a '99 306 with 72k on the clock. As I don't know for certain what condition it's in, and if the ratios are the same, I've used it for practise and to nick a synchro hub from. I picked it up on ebay for a fiver, and the best part is someone else had already removed it from the car

Here it is, stripped down as per Jim's guide:

I'm hoping I can swap the 3rd and 4th gear shaft as is, but I'll only know for sure once I can compare it to the one I take out of mine. If it differs, I'll need to use a bearing puller to get the hub off the shaft.

The Turbo Veg Sled, prepped for surgery and on the table.......

A couple of hours later and the suspension is off and one driveshaft removed. Fortunately I have recently rebuilt the front suspension and fitted new ball joints so everything came apart very easily.

More tomorrow hopefully!

Unread post by **RichardW** » 29 Apr 2010, 22:01

You didn't need to remove the struts really, but it will save them hanging about....

If you've not had the OS drive shaft out previously, it might be 'interesting' getting the bearing out

evilally · Unread post by **evilally** » 30 Apr 2010, 18:43

You're right, how does that bugger come out? I undid the 2 nuts, pushed the bolts back and turned 90 degrees as per BOL. Is it just a case of brute force after that?

Unread post by **CitroJim** » 30 Apr 2010, 20:46

evilally wrote:You're right, how does that bugger come out? I undid the 2 nuts, pushed the bolts back and turned 90 degrees as per BOL. Is it just a case of brute force after that?

Nearly

The BoL does not recognise what corrosion can do.

Get a big cold chisel, blunted on the end and a big applicator of precision percussion (AKA Club Hammer). Apply the cold chisel to the collar on the driveshaft just in front of the bearing on the gearbox side and give the end of the chisel a dead blow. Rotate the driveshaft 90 degrees and repeat. Repeat until the bearing slides out.

Ensure the "hockey-stick" bolts are properly loosened and turned through 90 degrees to ensure they fully clear the bearing outer race.

I warn you the bearing can be held well tight by years of corrosion and it can take a good bit of fighting to free it. Take care not to burr the collar edges as otherwise it'll get stuck in the housing and you'll never get it out unless you carefully file off the burrs.

Use a big hammer, not a toffee hammer, and really give solid dead blows. It'll free!

Good work so far on dismantling the gearbox

Well done!

As others will testify, intermediate bearings have always been my personal nemesis. I always have trouble with them although latterly the problem has been resolved; my hammer was not big enough

evilally · Unread post by **evilally** » 01 May 2010, 14:22

Success!

Not much room to swing a hammer under there. Bang it a couple of times...rotate....repeat.

Battery and airbox out:

BoL tells me to remove the subframe....is this actually necessary?

Work continues.....

spider · Unread post by **spider** » 01 May 2010, 14:26

No I do not think so, although its very tight for space especially if you have aircon as the piping is in the way

I'm going from memory, I've only ever done one 405 clutch (that was a late TD) maybe ten years ago, I vaguely remember it was not that nice though, sorry.

evilally · Unread post by **evilally** » 02 May 2010, 18:55

Fortunately no aircon to worry about!

Progress today:

Engine and box supported on jacks, ready to be unbolted:

A lot of wrestling about and the box finally came out. I couldn't get the mounting stud removed, it was in too tight. I removed the whole bracket, which proved to give me more space:

Looks like it's had a battery leak on it. I'm going to degrease and derust it, then give it a nice coat of hamerite.

Picture of engine bay:

More soon!

spider · Unread post by **spider** » 02 May 2010, 19:09

Ah, the battery tray with that is not uncommon, on my 205 its actually welded on (despite being bolted too!) I just gave it a really good wire brushing and several coats of hammerite a few years ago, all still good since, so you`ll be fine doing that on your 405.

Good to hear no A/C , I think fitting it was a bit of an afterthought given the pipe routing, taking a 306 as an example even though there is less space between the wings, its easier to do. (exception on a rhd 306 with AC being the clutch cable as its fitted in between the pipes on the bulkhead (lol) but this is getting off topic)

Things are looking good though from what progress I see you have made

evilally · Unread post by **evilally** » 03 May 2010, 14:47

Been doing a bit of shopping today, so far I have:

Valeo clutch kit, £104 delivered
Genuine Pug Diff Seals, £10 delivered
Shell 75w/80 PSA Gearbox Oil 2L, £13 delivered

Any other gearbox seals I should replace, if so where do I get them? I've also wrecked the 2 shorter gear links, so these will need replaced

spider · Unread post by **spider** » 03 May 2010, 15:04

I used an 11mm (I think it was an 11mm) open ended spanner to pop the gear linkages off.

Regarding seals, the only ones that spring to mind really is the rear crank seal if its leaking, although if you have no (bad) rear main oil leak I'd be tempted to leave it alone.

You could look at the input shaft seal (under the 'guide' if its got one, although again I do think its best left alone if its ok.

The plastic bushes for the release fork are worth checking and carefully inspect the fork for cracks at the 'fork' and on the arm on the outside of the gearbox.

evilally · Unread post by **evilally** » 03 May 2010, 16:07

Cheers Spider, wish I'd thought of that. Linkages are about £18 each

Anyway, got the old clutch off this afternoon:

Looks knackered to me! It's a Valeo, so I assume it's the original.

Unread post by **RichardW** » 04 May 2010, 12:09

Definitely replace the two nylon bushes that the release fork runs in. I would replace the input seal / guide bush - it comes complete from the dealer (although Vince aluded to the fact that GSF were now supplying them here) - worth doing as a) you don't want the seal to leak on your nice new clutch, and b) the new clutch will run smoother on a new guide bush.

You'll probably find the new clutch is not that much thicker than the one you've taken out - doesn't look that worn in the friction department...

You've still got the amusement of re-engaging the release fork. Might be tricky with it supported on a jack....

addo · Unread post by **addo** » 04 May 2010, 12:35

I thought the clutch looked decent, too. But - they're $600 here, so we are a little more optimistic...

As to the housings - after degreasing, I had a lot of stuff cleaned by wet blast with glass beads. It leaves a semi-polished sheen to the parent metal - much nicer than paint:

evilally · Unread post by **evilally** » 04 May 2010, 17:00

Thanks guys, I'll get those bits ordered.

As I'm a big n00b, I've never even seen a clutch before

I presumed this one was knackered as it was slipping when the turbo spooled up. Does this mean there could be something else amiss?

spider · Unread post by **spider** » 04 May 2010, 17:42

Assuming the cable is OK (probably self adjusting yes?) , its likely to be the springs in the cover (the 'fingers') , possibly someone changed the actual clutch disc itself but not the cover plate (a bad practise, should always change all three parts for best results)