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Rear axle leaking

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Rear axle leaking
#1
  This topic is about my 1966 MG MGB
LMR7187 Avatar
LMR7187 Lou Ruffini
wesley chapel, FL, USA   USA
1966 MG MGB
Hi all, pretty sure there is a simple fix (hopefully) but never dealt with the rear axle before.

So after having the B up in the air for a week or 2 to flush and clean the fuel system (rusty tank) I started to see fluid dripping down on to the rear tire. I assumed it was a bad brake cylinder... after ordering a new one i realized it was coming from the axle. The car is leaning a little more to the side that the leak is coming from but should that matter?

Also, I did change the rear end fluid about 6 months ago... is it possible i just over filled it and the excess is seeping out?

Thanks in advance, Lou

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oleanderjoe Avatar
oleanderjoe Gold Member Joseph Baba
Fresno, CA, USA   USA
Wishing wellls are a myth. It’s an axle seal I believe, if the wheel cylinder, brand line and bleeder show no signs of leaking.
Sorry, but it is easy to do. Do the other side at the same time Cheers


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ozieagle Avatar
ozieagle Gold Member Herb Adler
Geelong Victoria, Australia   AUS
1958 Wolseley 1500 "Wooly"
1966 MG MGB "Bl**dy B"
Hi Lou,

I have found that letting the car sit with the brake disk off, removes the pressure on the gasket and O ring in the hub, as the two Pozidrive screws don't seem to be able to retain pressure across the whole face. Easy enough to fix, new gasket and O ring, or just clean, replace the drum, and tighten. To replace the gasket and O ring you will need to drain the diff.

Unlikely caused by over filling, after all oil is meant to go there, to lube the bearing.

Herb



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oleanderjoe Avatar
oleanderjoe Gold Member Joseph Baba
Fresno, CA, USA   USA
HERB; Definitely think you nailed that one.????? CHEERS


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tsim Avatar
tsim Silver Member Tom Sim
Topeka, KS, USA   USA
1966 MG MGB
Hi Lou -- I just yesterday addressed an oil leak similar to yours on my 1966 MGB with a banjo axle. It turned out that the oil seal behind the hub bearing was bad.

Replacing it involved removing the axle shaft, removing the hub, pressing out the bearing from the hub, and replacing the oil seal.

I'm hoping this isn't your issue but if you still have a leak after replacing the flange gasket and o-ring, this might be your issue as well.

You might also check that the breather tube on the top of the axle on the right side isn't blocked. I understand if this vent is blocked pressure can build up in the axle causing a leak.

Good luck with your repair!

Regards -- Tom

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Donthuis Avatar
Donthuis Don van Riet
Rijswijk, ZH, Netherlands   NLD
While you have the banjo axle open on this side, check the presence of the spacer between the halfshaft flange and the bearing proper. It was missing in my case, heavens knows why and then leakage will return.There is no need to drain the axle fully if you jack this side a bit up, only the contents of the space behind the halfshaft flange will flow out. After remounting everything I always raise the axle higher on the other side to get this space refilled and then finish off by refilling the axle by its center filling hole as the last step.

Two more notes:
1) officially the gasket does not need any sealant on it, since the rubber O ring should do the sealing, but I found a thin layer of sealant provides extra protection against leakages
2) in case the oil seal on the inner side of the hub is leaking, you first need to buy this special octogonal socket with MOSS for undoing the nut and probably buy or lend a large puller to get the hub off the axle. Getting the seal out is from the backside, check the condition of the bearing before putting a new one in, you may have to press the old bearing out and a new one in first. Seal in is latest.
I feel you can re-use the locktab washer under the nut, recognising the very high torque value, alternatively use blue Loctite on the threasds as I did myself thumbs up

Hopefully issue (2) does not apply in the OP case, one needs a large press for such a bearing renewal job and this 50mm octagonal socket is quite expensive

In reply to # 3692567 by ozieagle Hi Lou,

I have found that letting the car sit with the brake disk off, removes the pressure on the gasket and O ring in the hub, as the two Pozidrive screws don't seem to be able to retain pressure across the whole face. Easy enough to fix, new gasket and O ring, or just clean, replace the drum, and tighten. To replace the gasket and O ring you will need to drain the diff.

Unlikely caused by over filling, after all oil is meant to go there, to lube the bearing.

Herb



Edited 2 time(s). Last edit at 2018-03-09 03:08 AM by Donthuis.

ozieagle Avatar
ozieagle Gold Member Herb Adler
Geelong Victoria, Australia   AUS
1958 Wolseley 1500 "Wooly"
1966 MG MGB "Bl**dy B"
Here is an extract from an article I wrote, telling how I made an octagonal spanner. Not mentioned is that I had to make a plate to hold it on the nut, as a PO had used a cold chisel on it previously.

Herb



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Diver648 Gold Member Warren Siringer
Tucson, AZ, USA   USA
1967 MG MGB
1967 MG MGB GT
1971 MG MGB GT
1974 MG MGB
If that seal is leaking, the other side and the pinion seal are probably getting close. I started removing my banjo rear end this afternoon to have all the seals replaced. When I drained the new fluid, it was black and I haven't even driven the car yet so I can't imagine what the inside will look like. Probably easier to do it all on the bench.

Boris67MGB Richard Boris
Kings Park. NY 11754, USA   USA
1967 MG MGB
Before replacing the hub seal; the seal surface on the banjo case nipples need to be inspected for grooving. If the nipples have worn in grooves; then a new seal is useless. To correct the grooving issue; if any, a speedi-sleeve will be needed to be installed. Note: these banjo axle's have been around for more than 50 years; so you can anticipate some degree of
nipple grooving. Also it is unusual to have a bad bearing unless it has been abused during installation/removal. They were designed for truck use and are built lake a battleship.

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Mustangsix Avatar
Mustangsix Gold Member Jack Collins
Orlando, FL, USA   USA
On the MGB banjo axle is the big hex nut on one side Left-hand thread like it is on T-series and MGA's?


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Donthuis Avatar
Donthuis Don van Riet
Rijswijk, ZH, Netherlands   NLD
YES (left rear wheel of course)

As a sidenote: I got this left side one off after bending the lock tab away & worked with a chisel and hammer on the nut. After buying a brandnew nut and locktab I put the nut back on with Blue Loctite
Not having bought the expensive eightsided socket for getting that 130lbf torque on the nut I had to use other means to get it securely fixed in place smiling bouncing smiley

In reply to # 3694439 by Mustangsix On the MGB banjo axle is the big hex nut on one side Left-hand thread like it is on T-series and MGA's?



Edited 2 time(s). Last edit at 2018-03-10 10:47 AM by Donthuis.

pop5948 Avatar
pop5948 Silver Member Wayne Telman
Townville, SC, USA   USA
So Lou, where did you end up with your repair. I am facing the same issue on my 66 MGB. Just noticed it this weekend. Of course it would be as we start driving season in the Southeast USA!

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jdriley83 Avatar
jdriley83 Gold Member David Riley
Macon, GA, USA   USA
1976 MG MGB "Reluctant"
I am pretty sure you can drop the opposite side you are working on a couple of clicks on the jack stand and not have the oil drip out the side you are working on. Even with the axle under the car you can have one side higher that the other enough so that the oil will not drain.

In reply to # 3692567 by ozieagle Hi Lou,

I have found that letting the car sit with the brake disk off, removes the pressure on the gasket and O ring in the hub, as the two Pozidrive screws don't seem to be able to retain pressure across the whole face. Easy enough to fix, new gasket and O ring, or just clean, replace the drum, and tighten. To replace the gasket and O ring you will need to drain the diff.

Unlikely caused by over filling, after all oil is meant to go there, to lube the bearing.

Herb

LMR7187 Avatar
LMR7187 Lou Ruffini
wesley chapel, FL, USA   USA
1966 MG MGB
Still anxiously awaiting parts from moss!!! Ordered a rear bearing kit hoping that will solve my problems...along with a laundry list of other odds and ends she needs... I'm starting to see why everyone calls them money pitsgrinning smiley... but most definitely a labor of love. Have been busy with rebuilding the SU's in the mean time. With driving season approaching soon I can't afford to be waiting on more parts!!! Thank everybody for the tips ill keep you updated.

Lou

Donthuis Avatar
Donthuis Don van Riet
Rijswijk, ZH, Netherlands   NLD
Always doublecheck whether the axle casing breather sitting on top is still OK. It is rare, but IF it is blocked, pressure will build up in the axle forcing oil past the seals eye rolling smiley

In reply to # 3695868 by jdriley83 I am pretty sure you can drop the opposite side you are working on a couple of clicks on the jack stand and not have the oil drip out the side you are working on. Even with the axle under the car you can have one side higher that the other enough so that the oil will not drain.

In reply to # 3692567 by ozieagle Hi Lou,

I have found that letting the car sit with the brake disk off, removes the pressure on the gasket and O ring in the hub, as the two Pozidrive screws don't seem to be able to retain pressure across the whole face. Easy enough to fix, new gasket and O ring, or just clean, replace the drum, and tighten. To replace the gasket and O ring you will need to drain the diff.

Unlikely caused by over filling, after all oil is meant to go there, to lube the bearing.

Herb

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