• Hi Guest! Being a Paying Supporter is NOT a requirement to participate at BCF. However, subscribing will help ensure we can continue to serve the LBC community for years to come. If you enjoy BCF and find our forum a useful resource...Please consider supporting us by **Upgrading**
    (PS: Subscribers don't see this banner)
Tips
Tips

TR4/4A Rear Main Seal TR4A

KVH

Luke Skywalker
Country flag
Offline
I have rear main seal leak. It's not exactly just a few dribbles. It's a bit more than that. I need to check further, but it looks like a good two tablespoons after a long drive and then sitting for a few hours.

Can I just watch the oil and live with this, or do I need to set aside some time to take the engine out and apart?

Life wouldn't be fun if these cars were flawless.

Oh, and I guess I should ask. The PO put a "lightened flywheel" in the car. I can tell it's probably good for performance, but it seems a bit harsh. Could that put more stress and wear on the main seal?

thx
 

Geo Hahn

Yoda
Country flag
Offline
2 tablespoons would bother some folk, I would be more likely to live with it and watch & wait (for a bigger reason to pull the engine).

BTW - a little oil goes a long way so if you're judging by the puddle perhaps it is even less.
 

Geo Hahn

Yoda
Country flag
Offline
Okay, I don't do much in the kitchen so I had to look it up -- 2tbsp = 1oz.

An ounce of oil everytime you park the car does sound a bit much (and probably makes you wonder what you lose at speed). I suppose oil consumption would be a clue to the latter.
 

Moseso

Jedi Knight
Offline
There is no contact between the stock oil seal and the crankshaft. The "harshness" of the flywheel should have no effect on the seal. Even if you have one of the later replacement oil seals, the seal is right behind the main bearing. It would take some pretty ferocious shaking to cause early seal failure. I don't think the flywheel is to blame.
 

RJS

Jedi Warrior
Country flag
Offline
More than the rear main seal, see if you can check whether the crankcase is venting properly. Even the smallest pressurization in the crankcase will push oil out the rear main seal.

The original PCV system on the TR4A was marginal at best. If you still have it in place, take a test run without it. Remove PCV and rubber hoses, cap the port on the intake manifold with a little rubber cap, and just run a 1/2" hose off the valve cover vent. Test drive for 20+ mins.

I used to get the oil leak just like you. With better crankcase venting I now only get one tiny drop after an hour of hard driving (and I suspect it is from a bad gasket on my fuel pump or timing chain cover).

Bob
 
OP
KVH

KVH

Luke Skywalker
Country flag
Offline
On my 4A, the prior owner removed the PCV and left the valve cover vent open. He also removed the block freeze plug and reinstalled the stock TR4 breather pipe.

So . . . it looks like I just have a bad main seal.

I rechecked the amount of oil. I suppose it's more like one tablespoon after 24 hours.
 

HerronScott

Darth Vader
Offline
KVH said:
On my 4A, the prior owner removed the PCV and left the valve cover vent open. He also removed the block freeze plug and reinstalled the stock TR4 breather pipe.

I'd try to find a TR4 valve cover with the TR4 vented oil filler cap if you already have the TR4 road draft tube.

Scott
 
OP
KVH

KVH

Luke Skywalker
Country flag
Offline
To replace the rear main seal, the crank must be removed? Correct? Aren't the bolts behind the flywheel?
 

TR3driver

Great Pumpkin - R.I.P
Offline
Yup, it's definitely an "engine out of the car" project. On top of that, there is a special tool required, and the dimensions given in the shop manual are wrong (as is the tool being sold by at least one major vendor).

BTW, there will soon be a new "improved" seal available through (Joe) Alexander Racing Equipment. Too soon to say for certain, but it sounds like it should work significantly better than the "improved" seals currently on the market; plus it reportedly does not require having the crank machined (so you can go back to the original if you choose).
 

MoHealey

Senior Member
Offline
Randall,
Digging up this old thread to ask yet another question...
Can you tell me where I might source the locating mandrel?
..one that's the RIGHT size, that is, for a TR4?
Thanks
Bill
 

TR3driver

Great Pumpkin - R.I.P
Offline

TR4nut

Yoda
Country flag
Offline
Roadster Factory is selling Joe's mandrel from the looks of it now...
 

M_Pied_Lourd

Darth Vader
Country flag
Offline
Yes was just going to mention it. Looks like the seal and the tool are in the special parts catalogue this week.

Cheers,
M. Pied Lourd
 

TR3driver

Great Pumpkin - R.I.P
Offline
eschneider said:
I'd love to hear Randall's input on the t-shirt and shellac idea.
Sorry, I don't have much to say, except that the felt seems to work for me.

One tip is to be sure you have enough felt. Easiest is to have an extra set on hand. You should not be able to get it all in, even beating on the drift with a hammer, so finish by cutting it off (leaving some sticking out to be compressed by the pan).

I cut the felt it into short sections (as per the book) and drop them into a shallow (disposable) dish of Permatex. When I tamp that into the hole, I can see the Permatex ooze slightly all along the joint ... no way is that going to leak.

But using T-shirt material should work just as well, and is a lot handier if there wasn't enough felt in the gasket set.

That's an interesting tip about cutting off the 'ears' ... I've changed the rear main bearing several times with the engine in the car and don't recall those ears being trimmed. But that may be differences in flywheels or something. I've not tried that with the project TR3 yet. In any case, I'll trim them next time.

I've not actually done many full rebuilds; been planning one for the past 20 years or so but never quite got a round tuit. It's amazing what you can do with the engine in the car! Don't tell anyone, but my previous engine actually has shims behind the rod bearing inserts, to close up the clearances with a worn crank. But the crank in the 'project' TR3 is surprisingly unworn (considering that the bearings were worn into the copper), so I left out the shims this time
grin.gif
 

MoHealey

Senior Member
Offline
Regarding the improved seal...
Any "complications" that I should expect with the one-piece design? Anyone actually ever installed one? I noticed that there is a core for the seal casting, so the mods to it can't be too severe.
It's pricey, and I would sure like to avoid ruining the thing in the process.
 

TR4nut

Yoda
Country flag
Offline
MoHealey said:
Regarding the improved seal...
Any "complications" that I should expect with the one-piece design? Anyone actually ever installed one? I noticed that there is a core for the seal casting, so the mods to it can't be too severe.
It's pricey, and I would sure like to avoid ruining the thing in the process.

I just finished installation of one of the new seals a few weeks ago. No more complicated than the other modern seals but without the need for modifying the crankshaft. And without the extra machine shop costs I think its pretty price competitive. Instructions were excellent too.
 
Similar threads
Thread starter Title Forum Replies Date
S TR2/3/3A rear main seal is leaking Triumph 13
Drone Dog rear main seal Austin Healey 13
T BJ7 Slipping Clutch? rear main seal? Austin Healey 11
Gerard 1098 10CC rear main seal conversion Spridgets 4
W A-40 Somerset - Leakage at Rear Main Bearing / Oil Seal Other British Cars 0
KVH General TR Rear Main Seal--Minor Problem Triumph 4
Editor_Reid Rear Main Seal for BN2 Austin Healey 12
J BJ8 rear main seal kit - is it necessary and worth the risk to install? Austin Healey 33
T TR4/4A Oil drain hole from rear crank seal/rear main cap Triumph 3
C TR4/4A Rear main seal Triumph 36
S TR2/3/3A rear main seal Triumph 9
E 100 4 Does anyone recognize this rear main seal mod? Austin Healey 12
KVH TR4/4A Viton Rear Main Seal Triumph 12
C Rear Main Seal Leak with Moss Retrofit Austin Healey 21
TR3driver TR4/4A "Mad Marx" rear main seal for TR2-4A once again available Triumph 10
KVH TR4/4A Rear Main Seal Leak TR4A Triumph 1
B Rear main seal kit Spridgets 3
O TR2/3/3A TR3 Rear Main Seal Triumph 5
A TR2/3/3A More TR3 Rear main seal problems. Please Help!! Triumph 8
tinman58 TR2/3/3A Rear main seal TR3 Triumph 11
P how to replace rear main seal in 1500 midget Spridgets 2
R Rear main seal question. Spridgets 29
MGTF1250Dave Improved TR Rear Main Seal Kit Triumph 19
B 1970 XKE 4.2 rear main seal Jaguar 2
M TR2/3/3A TR3 crankshaft rear main seal opinions wanted. Triumph 8
58Custom 1275 Rear Main Seal Kit- - seek info Spridgets 2
glemon Rear engine main seal review Triumph 7
J Moss rear main seal. Austin Healey 5
TimK Rear Main Seal Kit Installation Austin Healey 24
M Rear main Scroll Seal Triumph 11
A Rear Main Oil Seal Conversion - Bearing Cap debris Austin Healey 5
V TR6 TR6 Rear Main Seal Triumph 17
aaronclark TR2/3/3A TR3 Rear Main Seal Questions Triumph 7
T TR2/3/3A Tr3A rear main seal conversion - adviced needed Triumph 11
spartan0199 rear main seal kit 833-145 Austin Healey 12
A TR6 TR6 rear main seal housing special bolt ?? Triumph 1
fad64b TR2/3/3A Rear main seal TR3 Triumph 12
S TR2/3/3A tr3 rear main seal Triumph 6
A TR6 TR6, Best front and rear main seal ??? Triumph 0
C rear main oil seal Austin Healey 4
G TR4/4A And the fun continues...rear main leak Triumph 5
B General MG Solutions for topical MG rear main leak? MG 7
Martinld123 Drain Pipe Rear Main Bearing Cap BN2, remove? Austin Healey 2
Gerard 1098 "10CC" rear main Spridgets 0
S TR2/3/3A tr3 rear main Triumph 24
TraceZ rear main leaks Spridgets 3
B rear main Spridgets 5
B rear main puller Austin Healey 6
M TR4/4A Last question about original rear main sealTR3 TR4 Triumph 17
jlaird Installing the rear main cap cover correctly: Spridgets 3

Similar threads

Top