Gearbox Rebuild - Main Bearings Stuck on Shaft

Gearboxes, clutches, diffs, wheels & tyres....
tomsmy
Posts: 54
Joined: Sun May 22, 2016 12:55 am
Location: Alberta Canada (via Stoke on Trent, England)

Gearbox Rebuild - Main Bearings Stuck on Shaft

Post by tomsmy » Sun Jul 03, 2016 5:28 am

Hello All,

So my car has a bad bearing somewhere in the gearbox (really noisy but quiet when clutch pedal pressed, so i assume a bearing in the gearbox).

Before i take apart the one that "works" i figured i would learn to rebuild a spare first.

However I have encountered an issue.......

When trying (oh boy was this painful) to separate the front bell housing from the middle housing the Haynes manual says to "tap on the shafts with a plastic hammer" and they will come apart.....well mine did not!

I checked many times to be sure that i had removed all bolts and snap rings and after a good soak in deep creep I (rightly or wrongly) took a bigger hammer and a wooden block to it........

the result is as follows:
Attachments
Bearings (3).JPG
Bearings (3).JPG (239.24 KiB) Viewed 2504 times
Bearings (2).JPG
Bearings (2).JPG (224.97 KiB) Viewed 2504 times
Bearings (1).JPG
Bearings (1).JPG (219.08 KiB) Viewed 2504 times

tomsmy
Posts: 54
Joined: Sun May 22, 2016 12:55 am
Location: Alberta Canada (via Stoke on Trent, England)

Re: Gearbox Rebuild - Main Bearings Stuck on Shaft

Post by tomsmy » Sun Jul 03, 2016 5:30 am

So does anyone have some advice as to how i can remove the bearings from the shafts?

I was hoping they would stay in the front cover......

I would also appreciate if anyone can tell me what I should have done to avoid this rookie mistake......

Let the mocking begin!

thanks

Tom

TOOL
Posts: 2512
Joined: Thu Sep 01, 2011 10:30 am
Location: Var, France (ex NZ, ex UK)

Re: Gearbox Rebuild - Main Bearings Stuck on Shaft

Post by TOOL » Sun Jul 03, 2016 9:06 am

What you're describing sounds like the release bearing on the clutch fork.

Nothing to do with the box.
Back in sunny France

KiwiDave
Posts: 1777
Joined: Sat Nov 05, 2011 8:07 pm
Location: Feltham, Southwest London

Re: Gearbox Rebuild - Main Bearings Stuck on Shaft

Post by KiwiDave » Sun Jul 03, 2016 8:24 pm

Hopefully that is your issue as Tool suggests. I have the same issue with my gearbox. Not overly noisy but definitely something different when the clutch pedal is depressed / released.

I changed the release bearing but made no difference. However, if yours is a 'bearing type noise', then the release bearing is the easiest and cheapest option.
1985 Sunrise Red S3 TWR
2003 Mercedes E320 CDI Estate AMG

Daytona-Dave
Posts: 37
Joined: Thu Mar 10, 2016 11:32 pm
Location: Cheshire

Re: Gearbox Rebuild - Main Bearings Stuck on Shaft

Post by Daytona-Dave » Mon Jul 04, 2016 8:13 am

From the pictures above the box has had a fair bit of water in there which is the cause of your problem, you will need a puller to remove the bearings probably easier to go to the local garage and get them to remove them but that box will need a full strip down to check all bearings, i doubt it will be the release bearing as that would generate a noise when pressed,

tomsmy
Posts: 54
Joined: Sun May 22, 2016 12:55 am
Location: Alberta Canada (via Stoke on Trent, England)

Re: Gearbox Rebuild - Main Bearings Stuck on Shaft

Post by tomsmy » Tue Jul 05, 2016 3:46 am

Thanks for all the input guys. It's funny, this noise and the whole "clucth in or clutch out" and "is it in the clutch or is it in the gearbox seems to be very divided across the internet".

I will find out either way and report back when i remove the transmission from the car!

Daytona-Dave - thanks for reminding me that I should and can always see the local shops for help! it's funny how one can get absorbed at home and forget other humans exist and are able to lend a hand!

I will keep you all posted!

Thanks so much!

Tom

tomsmy
Posts: 54
Joined: Sun May 22, 2016 12:55 am
Location: Alberta Canada (via Stoke on Trent, England)

Re: Gearbox Rebuild - Main Bearings Stuck on Shaft

Post by tomsmy » Tue Sep 06, 2016 5:55 pm

Hey Guys!

So it has been a while since I last updated this post and long story short – as of Sunday night I have a spanky new transmission in the car!

So the bearing noise was the main (big) bearing on the input shaft that sits in the bell housing which explains why it made noise in all gears but was quiet when the clutch was disengaged.

My main learnings from rebuilding this transmission were as follows:

• If you press the clutch pedal in and the noise stops – the problem is in the transmission/gearbox.
• If you press the clutch pedal in and the noise starts – the problem is the release bearing.
• If you heat the bearings in the oven to around 100c or 200F they go on much easier!
• Take LOTS of photos during disassembly (your future self will thank you!)
• You will need long puller tools or your local shop
• You will need a custom tool to remove the lock nut

Overall it’s not too difficult to do, provided you have access to the right tools.

I will post some photos once I get home.

Any questions let me know.
Tom

codge
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Joined: Fri Apr 01, 2011 11:41 am
Location: South Yorks.

Re: Gearbox Rebuild - Main Bearings Stuck on Shaft

Post by codge » Tue Sep 06, 2016 8:15 pm

Not sure about heating release bearings....these things are usually sealed for life and heating in the oven could kill the inner grease and seals.
Gearbox internal bearings could conceivably be heated in an oil bath if you felt it necessary.

One more thing for the learning sheet......top of the list really....Mr TOOL is a man of few words, but his words are usually spot on. Read them and salute.

tomsmy
Posts: 54
Joined: Sun May 22, 2016 12:55 am
Location: Alberta Canada (via Stoke on Trent, England)

Re: Gearbox Rebuild - Main Bearings Stuck on Shaft

Post by tomsmy » Tue Sep 06, 2016 8:54 pm

Agreed about the release bearing, it slid on easily cold.

I will be sure to pay attention to Mr TOOL's comments and suggestions. I am certain that he, you and many others are far more skilled and knowledgeable than I.

Thanks

Tom

codge
Posts: 2599
Joined: Fri Apr 01, 2011 11:41 am
Location: South Yorks.

Re: Gearbox Rebuild - Main Bearings Stuck on Shaft

Post by codge » Tue Sep 06, 2016 8:59 pm

tomsmy wrote:Agreed about the release bearing, it slid on easily cold.

I will be sure to pay attention to Mr TOOL's comments and suggestions. I am certain that he, you and many others are far more skilled and knowledgeable than I.

Thanks

Tom
Sorry Tom, reading my post again it sounds a bit patronising.
I'm ancient, a good mechanic and bench fitter, but nothing like TOOL in knowledge of FB's.....I always look for his words when there's a complicated post.
Anyhow, we're all singing from the same sheet now.
Cheers
Dave

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