Gearbox input shaft seal extraction agony no more !

[LotusEngineeringBuff]

Hello,
Being in the midst of a chassis change I take the opportunity to change all lip seals (simmerrings) and gaskets on the engine and gearbox. It was such a pain to extract the gearbox input shaft lip seal! I just could not grab it from anywhere. I'm angry about myself to have marred the inner diameter of the front gearbox cover a bit while trying to bend the edge of the lip seal to be able to grab it with a pair of pliers. I had to touch the inner diameter of this cover a couple of 1/100th on the lathe to fix this.
Then, most importantly, in drilled and tapped M3 three holes at 120 degree on the front cover so that next time it will be a piece of cake to push out the front gearbox lip seal. I'm already looking forward to change this seal next time
I'm not saying I'm looking foward to pull the engine+geabox from the car to do it

Below is a pic of the modified front cover

[2cams70]

You really should be trying to avoid drilling holes. Once you drill a hole it's irreversible and furthermore in this case it's entirely unnecessary. The easy method to extract seals is with a screwdriver but don't do what most people tell you to do with a screwdriver and try to use it as a lever first up. First place a suitably sized screwdriver at the very edge of the seal and hit it with a hammer to try and fold the side of the seal inwards. Only then attempt to try and lever the seal out with a screwdriver. You may have to repeat on another side of the seal. Once the side of the seal is folded over the interference fit of the seal in it's bore is lost and so it becomes much easier to extract. You do of course require some feel and common sense to avoid damage to the edge of the bore that the seal sits in.

[LotusEngineeringBuff]

Sure: A hole is mostly irreversible, even if you plug it. But if it's tiny, does not weaken the part and is useful why not. Before drilling I did what you suggest: Use a small screwdriver and try to squeeze it between the cover and the lip seal to try to fold it inwards. It just was so tight and went so badly the scew driver left marks on the inner diameter of the cover. I do not want this to happen again. You are certainly more skillful than I am.

[joe7]

Could you post a side view picture of the bearing retainer?

[2cams70]

In my experience this seal is very reliable and it surprises me somewhat that a lot of you guys complain about it failing. You should get at least around 160,000km out of it before any signs of failure. I suggest that you avoid wasting your money on synthetic gear oil especially if you only ever use the car on road. Use the oil the gearbox was designed to use - ie a good quality mineral oil to avoid any chance of there being any rubber/oil incompatibility issues.

[2cams70]

Just a bit further to this - In some cases difficulty in removing the seal can be due to some previous numb-nut knocking it in too far. It only needs to go in as far so that the edge of the seal is level with the housing. This seal should not be difficult to remove. If the sideways folding of the edge doesn’t work easily then a screw driver inserted through the nose at the front and knocking on the front of the seal or access through the oil drain back channel should work. It’s been 20+ years since I’ve worked on one of these gearboxes so perhaps 512BB or promotor could chime in. All I remember is that removal was easy and didn’t pose any particular difficulty. Hole drilling certainly isn’t necessary.

Current project is a BMW ZF 5HP24 auto rebuild. These 4 speed Ford gearboxes are a distant memory now!

[LotusEngineeringBuff]

Could you post a side view picture of the bearing retainer?

Sure. Here it is with the oil seal installed. I hope that is what you wanted to see
Cheers
Francois

[gjz30075]

Is it backwards? I thought the spring was supposed to face the oil side.

[LotusEngineeringBuff]

Is it backwards? I thought the spring was supposed to face the oil side.

It is inserted correctly. Indeed the coil spring around the seal faces the oil side which is to the right side of the bearing retainer on the picture of my previous post. I'll try to make a better picture back home tonight.

[MACCA.GLM]

No need for drilling holes.I did this 3 months ago while checking out the box replacing the bearing behind the seal

A long thin punch down the tube on angle does the trick with ease.No damage to the seal housing.

Regards

G