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Problems with my Bush

Posted: Mon Oct 11, 2021 10:49 am
by silverboydreamer
This post is a heads-up for anyone who like me has had a continuing problem with variable tick over on a 356, the car is a B T6 and since putting it back on the road after restoration ( two years now) .
Over that time I have tried to find a cure for the problem, setup the carbs, replace the springs on the carbs, grease all cups and bearings including pedals etc but to no real improvement, so after having to put the car on stands for another small job I thought I would look underneath at the throttle rods and grease the cups. After disconnecting the cups off the accelerator pivot I found that the pivot was sloppy on the shaft but because the pivot is held in place by a large washer it is impossible to see what was cause, so off came the washer and I found no bearing on the shaft which is 10mm wide with the pivot barrel being 20mm , hence the movement. When I took off the pivot there was some sort of red residue inside the barrel but nothing else.
Looking at the official parts catalogue there is no bushing show for the car but by asking around I found out that the original plastic bushes had a habit of disintegrating over time and is not easy to spot because of the covering washer. However by looking on well known suppler websites there are nylon replacement bushes available, so I got hold off a couple to fit inside the pivot.
When trying to find the bushes they were not a straight forward fit as the bushes were slightly larger than the barrel, so I had to heat the pivot with a hair drier to expand the hole, this got the bushes inside the pivot but the pivot was too tight to go onto the shaft. The only way round this was to reem out the centre hole of the bushes with a 10mm drill bit, after this the pivot fitted easily onto the shaft and rotates without any sloppiness, so i fitted everything back and success, now the tick over is far more consistent, returning back to the rpm I set it to without any hesitation.
I hope this post helps, as with lots of these niggling little problems there is probably a solution know by someone, if we all posted our own solution that fixed them we all benefit.

Re: Problems with my Bush

Posted: Mon Oct 11, 2021 12:51 pm
by roy mawbey
Well done on that job and good of you to post. Its true if when the carbs throttle rods are firmly (with spring pressure ) against the end stops and so when you rotate by hand every ball socket on the throttle shafts each one, should be completely free of friction so the tick over should be constant. But if the accelerator has freedom of movement by excessive bush wear I guess that could upset the tick over. I notice if I am correct there is a difference in bell crank repair kits for 356A and 356B and C models.

To be honest I have never really taken my 356A version apart. I only use the thinnest of lubricant on the ball and sockets as I always wanted the movement of the throttle rods to the stops to be definate.
Roy

Re: Problems with my Bush

Posted: Tue Oct 12, 2021 9:37 am
by silverboydreamer
Thanks Roy,
I think any 356/ 912/ 911 that has a pivot with original bushes will have lost them by now,
A cursory look will miss the problem as the retaining washer obscures the problem.
Regards David k

Re: Problems with my Bush

Posted: Sun Oct 24, 2021 9:05 pm
by Ignatzcatz
What no bush jokes yet? Come on what's wrong with you.
So the man was in his back garden attending to the lawn but couldn't find his rake. He went to ask his wife but she was about to get in the shower, so he gesticulated at the ground, then his knee, then made raking movements at grass level. His wife gave a puzzled look then nodded and pointed at him. She then the pointed at her left breast, then pointed at her rear end, then pointed at her crotch. Of course, you left t'it behind the bush.
I'll go now

Re: Problems with my Bush

Posted: Mon Oct 25, 2021 9:05 am
by silverboydreamer
Well done, I did think a little provocative title might not only make the post noticeable but also encourage others to add something?