Throttle linkage cross-shaft question

[starbiscuit]

Just wondering if anyone has any tips for separating the two pieces of the linkage that run through the chassis rails?

The inner end, near the master cylinder (1970RHD bus) is OK, but the outer end that connects to the forward-going link rod has worn its hole to an oval. Lots of slop. It absorbs quite a lot of pedal motion without opening the throttle at the carb.

It seems the two shafts are joined by a roll pin, but I cannot shift it.

After ages bashing it (and my fingers) with hammer and drift I gave up. I just can't hold it steady enough and get enough of a whack on it to make any progress

Any ideas would be great.

Thanks for reading.

 

[Trikky2]

To dismantle you will probably have to use heat.

Alternatively just build up the oval hole with weld and then re drill the hole for a good fit.

(No need to remove it from the bus then)

 

[Happystamps]

Aye, they're a bloody nightmare, those. I ended up cuttting the bar out, drilling the remainder out of the ends and all the way through, cutting a new piece of 10mm OD bar to length- then welding the ends on to that. I figure it's a job I can afford to do every 40 years without issue.
You may find that the roll pin is actually a grub screw, but I can't quite remember.

 

[starbiscuit]

I'm pretty sure it's a roll pin not a grub screw.

The issue is that the 10mm shaft seems to have no bearings where it passes through the chassis, and there's a lot of wobble now that it's so worn.

Not sure how I could repair it without removing it, and I'd really rather not destroy it.

I thought about cutting off the face of the triangulated structure that the shaft turns in (that the horn bolts onto) and replacing it in two halves, maybe clamping the shaft between two halves of a replaceable bearing. If I could find anything suitable, that is.

The crank bracket under the accelerator pedal has a 6mm shaft running in a 10mm OD aluminium sleeve. Not sure if it's home-made, but it is also worn out. At least I can replace that one easily.

 

[Trikky2]

Ah - sorry. I thought you meant the hole in the arm was oval. Yes, if the hole the shaft passes through is oval then you can only fix it by first removing the shaft.

You could try heating the shaft and fitting. This might break the rust, seal between the two components.

The only alternative would be to cut the shaft and then sleeve weld it back together when you put it back.

As for the bracket under the pedal with the crank in it, your aluminium sleeve is a fix a previous owner must have done. You can drill out the spot welds that hold the bracket to the floor and remove it so you can then weld a steel sleeve into it to get rid of the wear and play. The bracket can then be welded or bolted back on. Alternatively the buttys unit can be fitted which looks to be well made.

 

[Happystamps]

I'm pretty sure it's a roll pin not a grub screw.

The issue is that the 10mm shaft seems to have no bearings where it passes through the chassis, and there's a lot of wobble now that it's so worn.

Not sure how I could repair it without removing it, and I'd really rather not destroy it.

I thought about cutting off the face of the triangulated structure that the shaft turns in (that the horn bolts onto) and replacing it in two halves, maybe clamping the shaft between two halves of a replaceable bearing. If I could find anything suitable, that is.

The crank bracket under the accelerator pedal has a 6mm shaft running in a 10mm OD aluminium sleeve. Not sure if it's home-made, but it is also worn out. At least I can replace that one easily.

I'd recommend not fitting it in two halves, the tolerances you'd ideally be dealing with are a little bit better than that and you don't want a notchy pedal. Do you have access to an oxy/acetylene torch? If not, and you really don't want to cut the shaft, you may need to find someone that does, I don't think a propane one will quite do it (by all means try).
Bear in mind that if you want to remove the shaft then you'll have to take the brake master cylinder out or remove the inner arm, which will be more difficult. Luckily the inner "hole" in the chassis doesn't wear nearly as much as the outer.

 

[VeeDubMan]

Do a search for Buttys Bits as I believe he is working on a bearing based bolt on soltion to solve this.

 

[gagvanman]

I had the same problem. Had to cut the old bar with a hacksaw blade at the inner side of the cross member. Got a length of 10mm stainless steel and a phosphor bronze bush. Drilled and fitted roll pins. (the photo shows split pins, but that was just to test the fitting):

 

[Trikky2]

I had the same problem. Had to cut the old bar with a hacksaw blade at the inner side of the cross member. Got a length of 10mm stainless steel and a phosphor bronze bush. Drilled and fitted roll pins. (the photo shows split pins, but that was just to test the fitting):

Nice work :mrgreen:

 

[starbiscuit]

That's a really nice job gagvanman.
I'm going down the phsophor bronze route for the pivot on the bell-crank immediately under the pedal.

Are those crank ends on the rod your re-cycled originals, or did you fabricate them?

Also, split-pins, if they are snug enough, should be good enough? I tend to think of roll-pins as fit once and never remove, because I have never managed to remove one that's been fitted for any time.

 

[Happystamps]

Split pins shouldn't be a problem. Bug throttle arms were a loose square shaft/hole and an e-clip which comes undone every now and then.