Technical 126 Syncromesh Gearbox Rebuild

[fiat500]

Stage 1 completed with the box stripped down,. During the course of this, one of my balls dropped I thought I found it but then realised that there is a fourth ball bearing which holds the speedo drive gear in place.
I've rebuilt a BIS box before, so this stage doesn't phase me although there are a lot of bits that need cleaning and checking. But it seems that the main expenditure will be on the 1st/reverse kit, whih is currently on offer at Axel Gerstl. The trouble is that these days, 150 Euro means almost £150.
MAL_4246 by Peter Thompson, on Flickr

 

[fiat500]

I found a fourth ball bearing; it was in the pan that I had drained the oil into.
It's smaller than the detent balls so I assume it's the one for the speedo drive. Can anyone confirm that to be the case please?

 

[Vitesse]

Ooh that is a bit worn that gear, it makes mine look positively new in comparison, it is slightly rounded but not to that extent.

 

[fiat500]

Ooh that is a bit worn that gear, it makes mine look positively new in comparison, it is slightly rounded but not to that extent.

Remember, in a previous life this gearbox was in a car (allegedly 500 but I doubt that) used by teenagers as a runabout in a field.
On the first point I should check the driveshaft lengths. They looked quite ropey before I cleaned up the ends to extract the drive flanges, but if they are 500 then they are definitely usable. In my deep storage shed I have loads of 500 gearbox bits that came as extras with the "yellow" car, so I will extract items from there and compare the condition of them.
I know that a lot of these things are actually quite inexpensive, but as Tony will know, these bits of cash really start to add up when you're sending a £100 order to Leo at VdL every couple of weeks.

 

[Bleeding Knuckles]

Hello Peter, Am very interested in your overhaul/rebuild - keep the pictures coming please. I will be most grateful for any info on your progress, especially in completing the turning torque of the differential roller bearing setting and the crownwheel/pinion backlash adjustment??????? I am having trouble getting the inner flanges to mate correctly with the bell housing (126 BIS gearbox to standard 126 bell housing)

Ian.

 

[Franko500]

Hi Peter,
If I remember correctly there are 2 ball bearings and 2 oval shaped ones.
the selector shafts use the 2 oval ones and 1 bearing. These are dropped through the hole in the top as you fit the shafts - bottom one first. These prevent 2 shafts from moving at once.
The remainder ball bearing I read somewhere is a safety item. it goes in the main shaft before fitting the speedo drive.
Have fun fitting this together. Its a great feeling when it works!
£150 seams a good price for the gear kit.
I ended up buying about 3 gearboxes in search for a good one rather than buying a new kit. trouble is they all seamed to come with an engine attached.
I might be looking at selling one of the 650 engines if anyone is interested. It will need rebuilding though!

 

[fiat500]

Thanks for that info Sean Franko500. I like that "about 3 gearboxes"
I've ended up with two fat, oval pins and one thin one. there are also three fat ball bearings and one smaller one.
What have I also ended up with? " about 4 gearboxes".
I may have been bidding against others here and accidentally won when I used Ibidder and realised too late to cancel it. I was going to spend the £150+ on the gears and then saw the 594 engine/gearbox on Ebay which is going to cost the same including delivery. I figure that this will most likely be off an early 126 and will therefore be syncromesh. There is only a low chance of the gears not being worn, but if salvageable I have an engine and ancillaries for the price of the gears.
You know what's going to happen....it will also be scrap and I will have to get new set anyway.:bang:
Ian Bleeding Knuckles, (un)fortunately I have no plans to disturb or replace the diff bearings and I have no advice or experience to offer. Do you have a thread about the gearbox problem so we can ponder it?

 

[cambio]

It could be off a 500R like mine which is none synchro... but probably not as the R is a relatively rare variant in the uk, having never been imported officially. If the carb is a 28IMB (has a fuel supply and return) its off an early 126.
If you haven't got a need for the engine I could be interested

 

[fiat500]

Yes, I expect it not to be from a 500R. I will bear in mind what you said because I am becoming quite well off in engines and gearboxes and somewhat less so in car restoration funds.

 

[the hobbler]

There is every chance that I will have a '650' engine for sale in the near future. It will be clean, free-turning and complete, but will need a COMPLETE overhaul. Contact me direct if you are interested.

 

[fiat500]

I detached the newly acquired gearbox from the engine and found a lot of oil residues inside the bellhousing. Although I'm pretty sure it's come from the engine via the rear crankshaft seal. I will have to replace the gearbox input shaft seal just to be sure. Fortunately I have a spare, brand new sintered brass bush for that; it would be handy if anyone knows the dimensions of the seal so I can get one locally. I degreased it as much as would come off without using evil stuff.
MAL_5879 by Peter Thompson, on Flickr
I think it will jump out of 1st gear as there isn't a huge amount of tooth contact going on; worth a try for my exploratory use of the engine and box.
The gearbox shows signs that it's been dismantled before and I guess this was in order to put 500 shafts in it.......whose engine box was this?

MAL_5877 by Peter Thompson, on Flickr

I also have a couple of new 25mm driveshaft seals and I have more confidence in using the existing tough-looking existing boots than I do in the repros, so full steam ahead to tidy it up and fit it.

 

[Vitesse]

Did you degrease it using grease???????:devil:

 

[fiat500]

Did you degrease it using grease???????:devil:

Maybe I should have said "pre-degreased it?"

I don't like using heavy solvents any more and the water-based stuff just takes the edge off it really. The outside needs scraping and going over again with panel-wipe before we achieve the concours finish that I favour which puts you all to shame.

 

[looigi]

Hi Peter,

I have found that the eco friendly, tree hugger, be nice to the birds stuff isn't worth having.

I always ask for the most evil, don't drink it, don't touch it, dont smell it, look at it through dark glasses variety and I have always walked away with smiles and gleaming parts. The most recent degreaser an engine reconditioner friend put me onto doesn't even kill my grass, but by god does it remove dirt and grease. It is called Super-Rip Universal Cleaner and Degreaser from a local company called Pacer. It even removes that brown varnish that you get inside the engine. Oh, and just to appease any members of Greenpeace reading this, it is green..... Green coloured anyway!

Chris

 

[ricardoreis]

Hi Peter,
It is called Super-Rip Universal Cleaner and Degreaser from a local company called Pacer (...) Green coloured anyway!

Chris

this!
http://www.pacer.co.nz/product-group/147/category/48

 

[looigi]

this!
http://www.pacer.co.nz/product-group/147/category/48

Yep, that is the one. I bought 20L and I use it undiluted for the nasty cleaning jobs. It works seriously well, but use it with good thick gloves and eye protection. I have never got it in my eye, but I suspect it would not be fun.

I am sure that there will be similar products available at a store near you.

As an interesting side note, at work we are getting huge amount of work from the new Boeing aircraft during their hangar visits now. A few years ago Boeing followed the PC brigade and stopped using the Chromate based paint primers in favour of a new eco friendly version. We are finding massive amounts of filiform corrosion on these jets now and they are only a few years old. Chromate primer was, like most aviation chemicals, straight from the Devil's kitchen, but it worked. The new stuff is toxic in all sorts of other ways and it doesn't.

Don't get me wrong, I am all for saving the whales, I don't like toxic chemicals where there is a non-toxic alternative, but I also like results. On that theme, has anyone had any success using molasses and water to remove rust? I am thinking of trying it out but I think Her Indoors might veto the idea on the basis of the smell.

 

[fiat500]

Thanks for the recommendations NZ-guys. I had a look at the data sheets for your chemical and mine http://www.toolstation.com/shop/Cle...s/sd3256/Swarfega+Oil+&+Grease+Remover/p10104
and the biggest difference seems to be that you have a bit of caustic soda in there. But the Supa-Rip is more than 90% by mass made of water.
The Swarfega stuff will be the same.:bang:
I loved the old "Gunk" and "Jizer" but I think they have changed a lot.

As for molasses, I think it works but still swear by diluted (or not) phosphoric acid. The photo shows part of the cowling cleared of rust by dipping for a few days. The coppery effect is copper deposited from the plumbing fitting blocking the outlet of my plastic dipping tank.
MAL_5964 by Peter Thompson, on Flickr

 

[fiat500]

Itis pretty obvious now that my recently acquired engine and box has been previously adapted for use in a 500. I find that all a bit strange because it should still be in a car, but that's another story I guess.
I've changed my mind again and want to keep the engine/gearbox pairs together. Having ordered a new first gear set just before the AG offer ran out and preferring that the Polish 650 box appears to not have been tampered with, I'm running with that one.
I haven't previously removed driveshafts so it was quite interesting to extract them from the differential on the second box. It's always touted as an easy job but I think it would freak out an inexperienced mechanic. It's amazing the load that those little pegs at the driven end must carry.
I've put the 126 and 500 shafts together for comparison; I know it's shown elsewhere but the difference in length is more than I realised.
MAL_6292 by Peter Thompson, on Flickr
Next thing is to degrease all the internal components of the box....don't worry, I be using proper stuff and it won't involve any water.

 

[Vitesse]

It's a right fiddly little job to get those little cogs and shaft back inside the crown wheel housing. If I remember correctly they kept falling out drove me batty until I got the technique right.

 

[Franko500]

They look to clean for your 500. There's no Patina!