Technical Cracked Gearbox Casing...

[MadMan0]

Hi all, after a torque wench failed the drain plug on my gearbox was over torqued and i's cracked the gearbox casing from the drain plug up along the side

Does anyone know what material the gearbox casing is made from?
I'll see if i can get it welded..

1997 mk1 punto 55s 5-speed manual

Cheers

 

[m20b25]

Does anyone know what material the gearbox casing is made from?

Cheese

But seriously, theyre made from an alloy. Personally I think you should get another box as theyre relatively inexpensive.

Ive seen your thread on economy and how to maxamise it further, how about a 6 speed from a 55? They were available with them just a matter of finding one...

 

[MadMan0]

Cheese

But seriously, theyre made from an alloy. Personally I think you should get another box as theyre relatively inexpensive.

Ive seen your thread on economy and how to maxamise it further, how about a 6 speed from a 55? They were available with them just a matter of finding one...

Oh cool, i hadn't thought about that..cheers
I'll have to check with my insurers first though then they'll proberly say it's a mod and will charge me an extra million pounds:bang: I'll look into it though thanks

 

[Brendan W]

I've seen successful repairs of crankcases with Araldite after a con rod punched out. I know it sounds a bodge but worth a bit of research and a try.
As for torqueing non load bearing fasteners I think it's a bit of a joke. Everything has to be just right to end up within an ass's roar of the desired result. Many critical applications are now angle tightened.Much better relying on feel.
Welding the alloy ? I wouldn't. Don't know what it is and what its heat treatment history is and a used box would be cheaper than an tasty welder.

 

[Mal126]

Hi all, after a torque wench failed the drain plug on my gearbox was over torqued and i's cracked the gearbox casing from the drain plug up along the side

Does anyone know what material the gearbox casing is made from?
I'll see if i can get it welded..

1997 mk1 punto 55s 5-speed manual

Cheers

Could always stitch weld it, , sorry suspect most won't know what that is, me being an old un !!
sorry meant stitch it, back together

 

[MadMan0]

i've currently smeared it with locitte high temp stuff, it's slowed the leak, but not stopped it

 

[fingers99]

t couod be TIG welded, but much cheaper to find another box. No one would look at it while still in the car, anyway............

 

[Ziggy122]

Unless its welded Properly - it'll be the weak point if it is to blow

If you have tool or got a mate to weld it up - should be fine

If not a Box might be on order

Ziggy

 

[DaveMcT]

It can be welded with Lumiweld its a low temperature system that's more like soldering bit its strong enough to reattach VW van gearbox mounting lugs.

BUT while Lumiweld works at around 350C, aluminium needs lots of heat so you need a big gas burner and the gearbox will have to be stripped out. IMHO not worth the effort. TIG is more concentrated but the local expansion at the weld site can cause cracks to appear as the metal cools down so it would have to be stress relieved = big burners again.

Moral: Never implicitly trust a torque wrench for everything. They are are the mechanic's equivalent of a Sat Nav, Useful for some jobs; indispensable for others, but most of the time a distraction from doing the job properly.

 

[Ziggy122]

To be honest - putting it on with a torque wrench is pointless
Its like the sump plug - You put it in till just starts to feel a little tight
As long as it doesn't leak - its not a problem

Ziggy

 

[MadMan0]

To be honest - putting it on with a torque wrench is pointless
Its like the sump plug - You put it in till just starts to feel a little tight
As long as it doesn't leak - its not a problem

Ziggy

Just following the haynes manual
I have learnt the lesson though
- There is nothing else wrong with the gearbox it's self so swapping it doesn't appeal as it's the gearbox that came with the car when new.. Low mileage

 

[Ziggy122]

Swap the gearing the gubbins into a Gearbox Casing then

If the G/box is leaking - it means the fluid isn't there to lubricate the gears properly = Gears run dry = Gets hot and then make to much contact and wear out

Dont mask the problem - get it sorted!


Ziggy

 

[DaveMcT]

Just following the haynes manual
I have learnt the lesson though
- There is nothing else wrong with the gearbox it's self so swapping it doesn't appeal as it's the gearbox that came with the car when new.. Low mileage

I feel your pain.

At least not like a guy I know who "ruined" his motorbike sump plug. It is a 17mm across flats alloy plug that happens to have a crosshead screwdriver slot in the top. He tried to remove it with a screwdriver and stripped the crosshead. OMG its ruined!!!

In a panic, he asked me to have a look and I just used a normal 17mm ring spanner - initially never noticed the stripped crosshead (its pointless anyway). I then had to make sure he understood which way to turn the spanner.

 

[MadMan0]

Update:
Lost most of gearbox oil in last 2 days:bang:

Went to Fiat yesterday, they said a Recon box ~ £1,500
or ordered new will be alot more as they don't make them anymore?:bang:

They also said that i would need to get the whole box not just the casing... Pain..

Will see how much i'm quoted to have it welded - otherwise i will proberbly be selling the car as £20 on oil every 2 days is too much

 

[Brendan W]

They're winding you up - 1500 !
Can't believe there isn't a used box out there , even if the innards are fried you can just recover the casting.
The plug is probably opening the crack so long term epoxy is a poor bet. I know of some folks who helicoiled the plug hole with a straight thread instead of the taper to reduce the stress on the repair. Find a good TIG welder in a gearbox rebuild company, machine tool or aircraft repair shop or check out the vintage car repair forums.
In the meanwhilst you could try some of the rtv sump elastic sealers.
This is not the first time this has happened - someone has done this successfully before you. google google.

 

[Ziggy122]

Mad man - go to scrappy get another Box mate
open both up and Swap the gubbins as long as the bearings and seals in the Scrappy box are okay

Sure the case wont be same milage - but the interials will be if swapped over

Ziggy

 

[DaveMcT]

Main dealer as ever taking the P in the hope you'll buy a new car. They are all as bad Fiat, Ford and the rest.

If the innards are OK strip them out and grind the cracks out with a narrow angle grinder disc or rotary file and fill with the Lumiweld. Don't grind right through because the stuff is like solder and it will run out. It wont stick to steel so you can put the drain plug in place while "welding". or you could have it re-threaded and use a top hat shape sump plug with copper washer. You will need a large propane torch to get enough heat into the casing but you dont need anything like normal welding temperatures.

TIG welding is also good as the cracks wont need so much grinding but make sure the casing is heated first and post heated to relax the stresses caused by the weld metal contracting after it hardens.

I have used the Lumiweld to repair a motorbike shock absorber foot. It is an duraalloy fork that connects the shock spindle to the suspension arm which had cracked because someone forgot the spacer washers. Its since done 10,000 miles with no signs of failure.

If all that is too much get a used gearbox from a breakers. get the work done by a small garage that wants to keep its customers. My guy yesterday found my funny rubbing noise fixed it and charged me nothing. I cant imagine any main dealer being so helpful.

 

[bredsticz]

Why go to the dealer for anything?
New gearbox on ebay for £50. Maybe even cheaper. I sold a mk2 gearbox for £50

 

[MadMan0]

sry to bring this back, The Loctite goo worked well but never stopped the leak fully, so i'm going to try "welding" the box with some solder
I'll try and get pics up to show the problem, the loctite "fix" then the solder "fix"
and see if we can sort this...

A recent knock put me off fixing the car as they (as ALWAYS) didn't leave details and fled the scene SO i'm trying to bring my self around by starting to fix it

 

[DaveMcT]

Loctite was never going to work. The only viable method is either TIG welding (and hope it does not cause stress cracks elsewhere) or Lumiweld. That is low temperature so no worries about stress cracks and it's very tough. However, aluminium has a high heat capacity so you will need a BIG gas burner to get the casing hot enough. Follow the instructions on the Lumiweld packaging.

Lumiweld is also more like soldering than welding. You have to do the whole job in one go. If you do one side and turn it over (as you would with TIG) the heat will just melt your first welds. It also wont fill large gaps. Not everything can be lumiwelded

You will need to strip the gearbox to do the job so TBH Ziggy is right. The best bet is to get a new gearbox case from a scrappies and swap your good internal parts over. Replace the bearings and seals while you are at it - input shaft at least.