Technical Problem with transmition, please help

[AndrewHarvey]

It is very easy / possible to mount the coupling back to front

 

[Paolo66]

I think the inner splined part is slightly longer; at the side that faces the wheel I think. It must bear on the centre part of the inner wheel bearing I guess?

You are correct Peter. There should be a raised inner diameter and this should fit against the wheel bearing in the housing

 

[gordinir8]

Looks like it is correct installed but I will take a closer look tomorrow

 

[Toshi 975]

If I understand well are you talking about part No.1 ?

I now that and I am planning to replace them with 24/25, besides they are cheaper also. I put a circlip on at the shaft but the coupling sleeve couldn't touch the rubber coupling so I put four spacers. Don't ask me what is going on it just look that the shaft is missing as I said in my previous post 2-3 mm. This is a temp solution until o/h.

There should be a spacer ring between the coupling and the bearing. The seal runs on it 's outer surface

 

[jjacob]

From September 1965 parts manual.
John

 

[gordinir8]

Which part you referring to John?
Thomas

 

[fiat500]

There should be a spacer ring between the coupling and the bearing. The seal runs on it 's outer surface

Very good point. Without that the whole bearing setup would almost certainly be wrong:bang:

 

[jjacob]

Which part you referring to John?
Thomas

Not referring to any particular part Thomas. Just thought a detailed view might help.
John

 

[gordinir8]

Ok as I said I'll take a look and let you guys now.
Thanks anyway

 

[fiat500]

Which part you referring to John?
Thomas

Mr. Toshi is referring to part No.890292. Sometimes it is missing It actually sits inside the seal No.411171. So the force exerted on nut No.4037820 is transmitted through the inner part of the rubber coupling , through the spacer and onto the inner race of the inner bearing then through the collapsible spacer to the inner race of the outer bearing. It is very important to the whole setup.
That drawing is very helpful John.

PS, John Thomas means something amusing to some of us Brits.
http://www.urbandictionary.com/define.php?term=John Tomas

 

[F123C]

You all probably know this already but for guys new to the 500 etc :-

Iirc the 500 uses a cardan? joint at the inner end of each driveshaft where they attach to the gearbox(transmission) under the big rubber boots.

If you pull the driveshaft too far out of the differential the little drive blocks can fall off the driveshaft cross-pin inside the big rubber boot.. To re-attach them you'll have to unbolt the rubber boot. To check if they're still in place correctly try twisting the driveshaft back and forth, minimal movement means they in place ok.

Al.

Don't worry Thomas and Al,part No.1 can't fall out unless something really disastrous had happened. That is the issue; to put in new driveshafts you need to remove and dismantle the differential.
By the way, you may know this by now, but the 19mm shafts can be directy replaced by 24/25mm ones both in the synchro and non-synchro box. Just make sure they are specified for the 500 box.

https://www.fiatforum.com/500-classic/445012-difference-126-v-500-25mm-driveshafts.html

Peter, Thanks for the correction and putting minds at ease over this.
I was mistaken (as in wrong! ) that part No.1 can fall out on the 500.

But it can most definitely fall out of place on the 850 and I think also the 600 which use a very similar (but not the same) transmission design as the 500. Incidentally this part No. 1 being able to fall out of place means that the driveshafts on the 850 and possibly 600 models can be removed/changed simply by disconnecting the coupling and rubber boot and withdrawing them, no gearbox dismantling being necessary!

Al.

 

[fiat500]

the driveshafts on the 850 and possibly 600 models can be removed/changed simply by disconnecting the coupling and rubber boot .

I hope that arrangement was carried forward to the 900cc Fiat vans as it might make life simpler on my Amigo? I had already spotted the reassuring similarities back there under the vehicle. It certainly seems to be the way on modern, front-wheel drive cars.

 

[F123C]

Peter, yes I believe so. I worked on some 850T's (back in the day, our parts dept had one!).

Iirc the 900T engine can be livened-up a bit by using parts from the 850 Sport/Coupe which also had the 903cc engine.

Al.

 

[fiat500]

Thomas, a bit late but just spotted a photo in my collection of the spacer and a new coupling with the longer inner showing.
BRA_9338 by Peter Thompson, on Flickr
BRA_9547 by Peter Thompson, on Flickr

 

[gordinir8]

Peter thank you, an hour ago as i was driving on a hill it start kicking a couple of times from the l/h shaft. I drove back home and noticed that the drive shaft can move again in and out, probably the circlip is out of the groove again. Dont know what to think. Rubber couplings are not the same at both sides but you can't put them inside out since the thread of the 4 bolts is only on one side, mine are correct installed. Last thing i want to do now is to mess with this since i am planning to put a 650 engine untill summer.

 

[gordinir8]

Maybe a Gentleman can be so kind and since today is Sunday can go and crawl under his little car to take for me those three dimensions ''see attached picture''
Also if not a problem i would like also to know if you withdraw the rubber cover how much (if any) of the splines are exposed.
Thomas

 

[Paolo66]

Thomas
A = 83mm
B = 37mm
C = 45mm

Damian

 

[gordinir8]

Damian thank you, going now to measure mine and be back...

 

[gordinir8]

Damian thank you, going now to measure mine and be back...

Ok here is mine:

A=74
B=28
C=46

So i guess i am using the correct coupling but i am missing 1 cm and if i judge from Peters picture above that 1cm might be from the ring spacer.
I will disassembly mine maybe later today and see what is going on.
Thank you again Damian:slayer:

 

[Paolo66]

I would guess that you are missing the spacer. This is needed as otherwise your flexible coupling would be rubbing on the bearing housing