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re: TR4 Rear Main Seal

To: timipurdy@citlink.net, triumphs@autox.team.net
Subject: re: TR4 Rear Main Seal
From: CarlSereda@aol.com
Date: Tue, 8 Jul 2003 20:01:22 EDT
Tim,
I HOPE YOU CAN HANG IN THERE AND GET IT DONE WELL.
If you have a qualified mechanic who is quite familiar with TRs and is 
paranoid about the rear seal leaking - it's probably going to leak. Maybe a 
little, 
maybe a lot.
To set up this type of 'metal to metal' crank scroll seal correctly (and 
reliably) the motor should be out of the car and upside down - and requires a 
rare 
mandrel 'fitting' tool. Your mechanic can't feel confident without pulling 
out your motor and using a mandrel.
If one can't get the authentic Churchill mandrel I am told a cut off TR crank 
and some sewing thread (to fill bearing clearance) can be used similiarly. 
Some folks get the rubber seal upgrade (see Moss catalogue) - rubber rear 
seals have become the automotive standard starting around mid '60s - they 
forgive 
wear better. But I believe a properly installed new aluminum seal is fine IF 
YOUR MAIN CRANK BEARINGS ARE WITHIN FACTORY SPEC and you DON'T HAVE EXCESSIVE 
CRANKCASE PRESSURES from overly worn piston rings.
With heroics there may be a slight chance of slipping in a new aluminum rear 
seal and getting it centered with 3 thousandths of an inch all around - 
without removing the motor - but there's an extremely slight chance of getting 
it 
just right.
You don't tell us what your mechanic has done here. What exactly did he do? 
Install new seal? reinstall old seal? Eyeball it? What is his recommendation? 
I DO RECOMMEND HEEDING HIS CONCERN.
One worst case scenario might be: if your mechanic could get the old aluminum 
seal out from below, perhaps he got a new one installed (hopefully without 
damaging crank bearings and front seal..). Then he must have tried to center it 
by eyeball. But if he used a NEW aluminum seal, even if he is OFF the 6 
thousandths max that's built into the seal - it's probably better than re-using 
an 
old seal and being off say 25 thousandths - you'd have a real oil trickler 
there. Working with 'motor in' would also make it hard to get everything 
surgically clean and the joinings sealed up as required.
Sorry for the doom and gloom - don't want you to find out just how fast a 
garage oil drip pan can overflow ..
Have a closer look and be sure to hear out your mechanic.
Carl
'63 TR4 since '74


>>I took it to a qualified mechanic, to take care of those problems. He told 
me he owned a TR, so quite familiar.  Anyhow, he is very paranoid about the 
replacement of the rear main seal and specifically no guarantees that it wont 
leak.  Is there something unique about this process..
Tim<<

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