405 Gearbox Rebuild and Clutch Change

evilally · Post by **evilally** » 14 May 2010, 21:19

Thanks very much Jim, a very good read.

Progress tonight:

Reassembly started with new shaft. Mating face cleaned up:

Looks like this box has seen some serious heat, look at the scortch marks on this:

Upper casing is in a parrafin bath overnight.

More tomorrow.....

addo · Post by **addo** » 14 May 2010, 23:28

That's odd! I wonder if it has been post-heat-treated sometime in an effort to reduce wear?

Nice "workbench".

Mine are a scabby mess of gouges and paint splatters.

Post by **CitroJim** » 15 May 2010, 06:13

Coming along a treat Ally!!!

The "heat" marks on the selector are nothing to worry about. A remnant of flame hardening. Those tips need to be very hard...

addo · Post by **addo** » 15 May 2010, 08:57

So that's normal for a BE series box?

Glad I know now, not whenever the time comes to pull one down!

Without foreknowledge, I'd have been peaking and whipping the thing off to an aircraft tech for Rockwell or Brinell testing.

evilally · Post by **evilally** » 15 May 2010, 19:04

Today's progress......

All components assembled:

Main casing cleaned and refitted with loctite silicon gasket seal:

5th gear components assembled:

All gears turn over just fine

Two top nuts torqued to 70lb/ft, I'm not sure about the casing bolts, I just nipped these up fairly tight.

I've painted the endcap as it was corroded, so it's drying now. I'll fit that along with a new clutch sleeve, driveshaft seals and fork bushes tomorrow.

I'll also need to look at the bearing preload, hope that won't be too difficult

evilally · Post by **evilally** » 16 May 2010, 14:16

Right then, on to the tricky bussiness of preload

I have measured the depth between the bearing face and casing face, at the point where the bearing "just starts to drag" as instructed by BoL. This came out at 4.9mm. Surely this is somewhat subjective, as different people might perceive "justs starts to drag" slightly differently?

The spigot protrusion on my new bearing sleave is 3.6mm. So doing my sums I need a shim of 1.3mm thickness.

However.....the shim that came off the box that the replacement shaft came from is 1.2mm. Is it possible that the shim is matched to the shaft, and my measurements are a little out due to the previously mentioned subjective element? The shim from my box is 1.7mm, which is obviously no good.

Additionally, wouldn't there also be a variance depending on how tight the bearing sleeve was torqued up, as the spigot would protrude more or less inside the casing?

Hurmph....

evilally · Post by **evilally** » 16 May 2010, 15:42

Well, I doubled checked the shim thickness again, and it was 1.3mm. It looks like everything's worked out perfectly. I have to assume the shim is matched to the shaft, or I'm very lucky.

Anyway, one rebuilt BE3 gearbox

New driveshaft oil seals, bearing sleeve and fork bushes (all genuine Pug).

I'm not looking forward to trying it out for the first time, there's a lot that could go wrong, and a lot of places it could leak.....

jgra1 · Post by **jgra1** » 16 May 2010, 16:31

very good ! John

Post by **CitroJim** » 16 May 2010, 17:51

Ally,

Excellent

A very, very, very well done... Take a bow...

You have now mastered the art and gone where many fear to tread..

Your next task....

An autobox...

evilally · Post by **evilally** » 16 May 2010, 21:54

Thanks guys! Autobox.....no chance. I always say, if you can't be bothered changing gear, you might as well take the bus

Progress tonight:

New Valeo clutch kit installed:

Gearbox back on:

Getting the box back on was a complete s**t of a job. It took 3 of us about 3 hours to manoeuvre the thing into position. For the benefit of other people, it's much easier to remove the speedo drive housing and the static gear linkage plate at the back of the box. This gives you a bit more space. I would even consider removing the sub frame next time.
Luckily, the fork located first time in the pressure plate.

Now if the box doesn't work properly after all of this.......

More tomorrow possibly, I might have an evening off.

Post by **CitroJim** » 17 May 2010, 07:48

I reckon the hardest job of all is getting the gearbox back in position, especially, it seems, when you use a Valeo clutch...

I could have offered a few hints if the job proved impossible, paramount is to get Xac to bear-hug the 'box back in position

Can't agree about autoboxes; I love 'em

One has enough to do these days when driving without having to worry about gears and clutches...

Must be my age.. Pass me that mobility scooter catalogue please...

evilally · Post by **evilally** » 17 May 2010, 22:44

You're right, it's a nuisance changing gear when I'm on the phone and drinking my coffee

Update! I was in the zone tonight, and it got dark before I knew it so no pictures. I got the engine/gearbox back onto it's lefthand mount. Clutch is re-attached, and damn...it's smooooooth

I can't believe the difference, I would be very impressed even if it were a brand new car.

Got my new gear linkages fitted (£18 each

), gears are selecting fine.

Took my time and got a lot of other bits cleaned up and de-rusted.

I've just texted the boss to say I'm taking tomorrow off, I reckon I can finish this thing. To do list is to refit all the peripheral gearbox components, fit new CV boots and whack it all back together.

Fingers crossed it all actually works....

jgra1 · Post by **jgra1** » 17 May 2010, 23:58

let us know

evilally · Post by **evilally** » 18 May 2010, 20:17

Guys, I'll skip the progress pictures and get straight to the point. The whole thing is a disaster. I got things re-assembled enough to run the car on the axle stands. It sounds horrendous

It makes this noise in neutral and in any gear. The noise goes away with the clutch down. On the plus side, 3rd gear no longer crunches

Jim, what's gone wrong!!

:bigcry::bigcry:

Post by **CitroJim** » 19 May 2010, 06:02

Oh dear

That does sound a bit nasty...

I'm not even going to ask the obvious question about oil...

The new shaft; did you count teeth and ensured it meshed perfectly with the other one? There may be just enough difference to make it incompatible..

Something sounds like it is rubbing....

Are you sure the clutch went back correctly?

I think there is no option but to have the 'box off again and recheck...

And then 'box apart again. Recheck the preload and more carefully compare old and new shafts.

I know it's frustrating but these things happen...

I've been there with an autobox.