Gearshift linkage roll pin

[AndyBaur]

Ignoring the "if it ain't broke don't fix it" rule I pulled the gearshift linkage out of my '83 320/6 5 speed.

I had bought the 1.9 Z3 short shift lever which is one piece as opposed to the E21's 2 piece. This means I can't use the E21 gear lever spring or is it redundant with the Z3 lever? Also, the bottom knuckle seems to be too wide to fit through the E21's bottom cup. I thought the Z3 lever was a straight swap?

I got a new linkage & knuckle but can I hell get the roll pin back into the knuckle. It looks as though I need to disconnect the prop & move it over to get enough clearance. Is it just a case of unbolting the guibo? The Haynes manual says fit a 'compression ring' to the guibo - can I just use a large jubilee clip or does it need to be stronger?

[Jeroen]

Can't really visualize this one, can't you post a photo with both versions?

[nas80]

Z3 bottom bit is longer. You might have to get creative with the bottom rod

Unless you got it the wrong way round

[AndyBaur]

I don't know what happened to my last post - it just disappeared.

Anyway - this is the new linkage for the E21 with the Z3 lever temporarily fitted -



The problem I have is with the roll pin on the far left (p/n 15 in the diagram below). I simply can't get it into the knuckle (p/n 16) because the propshaft is in the way.


I have removed the 3 propshaft-to-guibo bolts but there isn't enough clearance to swing the prop out of the way. Next step is to undo the 2 centre bearing mounts & drop that down. Hopefully that will give me enough room to swing the prop over get the pin into the knuckle.

The second problem is the Z3 lever. I know this is a common mod for E30's & read that it works with E21's too. However, as you can see the bottom arm of the Z3 lever won't fit through the E21 bottom cup -


. . . and neither will the E21 top cup fit over the Z3 lever -


The E21 lever is in 2 parts with loads of washers, spacers & stuff inside and a spring that mounts between the lever & the top cup. The Z3 lever is a single piece unit with no provision for the spring. Some cost-cutting has taken place too - the E21 lever has a metal ball whereas the Z3's is plastic.

I should have heeded the warning - "If it ain't broke, don't fix it".

[Jeroen]

bummer!

[AndyBaur]

I still haven't been able to get the roll pin back in. I disconnected the propshaft at the guibo & at the centre bearing but there isn't enough clearance to swing it out of the way. I assume I will have to disconnect it at the diff too. Access to the bolts is very limited & the two top bolts on the exhaust flanges are seized & rounded so removing that will be a real pain too. So, I don't want to go down this route unless I really have to.

I can't be the first person to change the linkage bushes. Can this be done without dropping the prop?

[Jeroen]

Yes it can. If you undo the props center bearing and gearbox support bracket you have enough, only just, to remove the prop.

[AndyBaur]

So I only need to drop the front part of the prop? Excellent!!!

Thanks Jeroen

[Jeroen]

Just keep an eye on the cooling fan when tilting the engine and gearbox combo!

[AndyBaur]

Well I managed to sort the problem - Jeroen

I first removed the fan to avoid any expensive radiator issues.

I then disconnected the prop centre bearing bracket (the exhaust held the prop up).

Next, I supported the gearbox on a scissor jack (more controllable than a trolley jack) & undid the gearbox crossmember.

I lowered the gearbox as far as it would go. There was now enough room to get the roll pin into the bottom hole of the knuckle. I had previously got a new pin into the top hole in the knuckle but there wasn't enough clearance to get it fully inserted. However, this held the knuckle in place while I tapped the new one in from below.

It's probably worth sharing some knowledge I gained doing the job.

The diagram below shows the linkage.



Unless the knuckle (16) is worn or damaged you won't need to replace it. Part 14 (originally rubber, now 'plastic' [p/n 25.11.1.434.194]) deteriorates with age & oil - mine had crumbled completely. If you get a new knuckle there's one pre-fitted but you can buy them separately. They are like very firm headphone foam ear buds. They are surprisingly awkward to compress when re-fitting the knuckle. Incidently, new knuckles have a superior wire retaining ring rather than the awkward band (13) on the originals. Before you refit the knuckle, inspect the shaft it fits on. There's an oil seal on the shaft which leaks (probably why the bush disintegrates). The workshop manual says to just pick it out & install a new one. Good luck with that.

The 'Straight Selector Rod' linkage can corrode on the pins through the bottom of the gear lever (lots of swearing to remove). New ones come with 'lift tab' clips instead of circlips. When I got the plastic washers to go either side of the gear lever knuckle I found they didn't fill the space sufficiently (unless I put a dozen on!) so I spaced them out with some thick washers either side of the gear lever knuckle & the gearbox knuckle.

The Z3 gear lever does not fit through the E21 cups - the knuckle is too wide to pass through the bottom cup and the shaft is too thick for the top cup to pass over. Don't worry - with a new bush in the knuckle it will feel like a short shift.

When it's all done it will feel like a new car

[Jeroen]

the gear shaft seal is a pita indeed, you can pry it out but make 200% sure the shaft is smooth or you'll damage the new seal right away. And then even, replaced it 3 times on my E21 box already and it never stopped leaking

[mcjjordan]

Anyone tried to ream the pin hole out and fit an oversized pin as mine has movement in it

[mcjjordan]

Anyone?
Mines got masses of play left/right so much so now that i cant tell weather im in 3rd or 5th

[AndyBaur]

I don't think you can ream the roll pin hole in the shaft out. Even if you got an oversize pin to fit perfectly it would be too big for the knuckle & that would have to be modified exactly to fit.

How loose is the roll pin in the shaft? Is the pin a good snug fit in the knuckle? It's more likely the roll pin is undersize.

With the new knuckle (or foam insert - see my post above) and new straight selector rod (packed out with washers if necessary) you will find all the play is taken out.

The roll pin just holds the knuckle onto the gearbox selector shaft. It doesnt have to be super tight because a) the foam pad is under compression and b) the 'Tension Bush' band (p/n 25.11.1.203.682) holds the roll pin in place so it can't fall out.

The foam pad in the knuckle is key to a slop free linkage. It seems to do more that anything else to tighten things up.

Good luck.

[Jeroen]

Fully agree, could be this is missing or worn, and the most freeplay usually comes from the linkage that hooks up to this rod.