Paint on Inside of Diff Cover

[AHM]

Hi All,

I have the diff out after only 150 miles. The pinion seal was leaking.

The seal wore due to surface rust on the flange, that formed in the 3 years since rebuilding it.

I noticed that the seal I took out seems a bit soft and that the leaked oil was stripping the paint off the chassis, also silver bits in the oil.

So I've taken the cover off only to discover, that the silver is some kind of paint on the inside.

Has anyone come across this before? Or is it the good work of a PO?

[vernon.taylor]

Salut

I saw some paint-type treatments at a classic car show for treating and sealing the inside of petrol tanks, amongst other things; and I've heard of paint-type sealants for porous ally-wheels. I didn't ask at the stand but I imagine they would have said that their product wouldn't flake off if applied correctly

I wonder if you would have had surface rust if you had used the car more than 150 miles in three years - the seal relies on a film of oil to lubricate it against the rotating pinion.

@+

Vernon

[AHM]

Salut Vernon,

She has been off the road for 7 years, diff rebuilt 3 years ago - nice clean shaft no oil - because of the shape of the seal you can't see it until you take the flange off.

150 miles is running in since mid Feb.

[512BB]

The only internally painted diffs I have seen were finished in a red oxide type of paint, that remained intact, so long as the surface was surgically clean prior to painting.

Here is a picture of one such that I rebuilt. It seemed a shame for it to be hidden away unseen, so I had a glass back cast for it, identical to the Lotus ali casing. In the car now, and looking great.

A little tip for you Simon. The outer shaft on the diff flange should be coated in grease when rebuilding, oil will drain away very quickly and damage the rubber seal when it is first turned, as you have found out. The same goes for the front crank pulley, and the rear crank oil seal.

[Bud English]

... It seemed a shame for it to be hidden away unseen, so I had a glass back cast for it, identical to the Lotus ali casing. In the car now, and looking great.

...and you were using the multimeter to check gear backlash. No, wait the date on the post is April 3rd, not the 1st. A glass diff housing?

[john.p.clegg]

I do like these transparent housings.....cam cover anyone?

John

[AHM]

A good tip Leslie. I usually use Graphogen, but have had issues using it with seals so I use Oil, but grease would be better for storage.
This was assembled clean and dry for sealing the splines - then it can't be seen so was forgotten about.

The saga continued - I put the diff back together, filled it with 1.2 l of oil, put it back in... I was just tightening the driveshafts when I found the diff brace bolt - Which needs to be put in when the diff is loose as it is shrouded by the cross member - You can imagine the language.

Eventually I finished at some ungodly hour and went for a short but spirited test drive... not much traffic at 2am!. As I shut the garage door I noticed oil where the car had stood - Opened everything up lay on the garage floor and saw oil dripping from the diff.

Cracked diff housing? porous casting? bad seal? Uncured sealant? Oh well I'll find out later in the morning when I take it out again - more bad words!

Up early yesterday I cleaned everything-up, checked for cracks, tightened the bolts a bit and went for a short drive. I got back, took the wheels off and identified that it was coming from the breather, which is of course completely inaccessible.

As one does at moments of despair and national crisis I stopped for a cup of tea ...and a read of the manual. I just couldn't understand how oil would come out of the breather..... Checked the oil grade EP90, checked the capacity 1.2 l ... but wait 2 pints doesn't equal 1.2l. Another error in the manual!

Tea brake over I decided to remove the fill/level plug (the clue is in the name) to check the level, as I have always done in the past! Out gushed the oil - enough to make a great oil producing nation.... such as Scotland proud. (My diff must have been made in Scotland - it has a little oil, keeps whining, and it wants to be out of the car.) ironic as it is a ford English Diff - perhaps it was named by an American.

Problem solved - Manual in Bin

[Quart Meg Miles]

..... Checked the oil grade EP90, checked the capacity 1.2 l ... but wait 2 pints doesn't equal 1.2l. Another error in the manual!

Problem solved - Manual in Bin

So what does it equal? My calculators show 1.2 l = 2.112 UK pints which is only 5% different and hardly the cause for a flood.

I guess you poured in 2 litres!

[AHM]

I guess you poured in 2 litres!

No, exactly 1.2 l and I still have the remaining 800 ml in the bottle.

My calculator shows that 2 pints is 1.14 litres - so 60ml too much. I've no idea if 2 pints is correct either.
But what I can say is that it is enough that it comes out of the breather. So I'll go back to sticking my finger in the hole from now on.

[john.p.clegg]

"as the woodpecker said"

http://www.colombohash.com/content/woodpecker-song

John