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Old 02-25-2008
NH Bill's Avatar
NH Bill NH Bill is offline
1983 FC 35 "Casa Billisa"
Join Date: Jan 2008
Location: St. Petersburg
Posts: 3,833
Default 1. Fuel in the Valley slow fuel drip. 2. Valve lashing... Can it wait?

"I have changed a leaky throttle rod seal, and a few other gaskets without removing the pump , to stop the fuel in the valley leak."

Hello all,

Two issues here:

1. Fuel in the Valley slow fuel drip.
2. Valve lashing, can it wait?

I am new at all of this... pretty handy, but no mechanic. This is in reference to our new to us 1983 FC,

I have fuel in the valley and am not sure of the source. There is a fuel drip to the ground (every 15+- seconds) from one of three small tubes (bleed tubes?) that extend from the pump downward and terminate near the frame rail on the driver's side. This drip seems to have started when the cold weather set in.

Additionally, the hose that comes off the t-valve at the top of the pump (return line?) is failing and leaking a bit ( drop every 30 +-seconds) This hose needs to be changed. Its bulging and cracking (it looks like it is melting into one of the injector lines near its attachment to the pump).

I'm wondering if I can fix this myself?

For reference, I recently changed out the transmission cooler lines and that was a manageable project for me. Are these issues similar in difficulty or am I getting into tougher territory?

The coach has just under 75,000 miles on it and seems to run just fine... but we have not been out on a significant run yet. No smoke, starts instantly, sounds good, runs up to 65 etc.

I hear that I should have the valves lashed. I'm in contact with the original owner and he does not recall having this done and the records don't show it. Is this something that can wait a while?

Your feedback is always appreciated.

Bill and Lisa Garamella
83 FC-35 SB "Casa Billisa"
2006 Jeep Liberty CRD
St. Petersburg, Florida
Wanderlodge Social: https://mewe.com/profile/5bfc750ae760be22b1797898
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Old 02-25-2008
Randy Dupree's Avatar
Randy Dupree Randy Dupree is offline
Forum owner
Join Date: Dec 2007
Location: Port St Joe,Fl
Posts: 36,240

the line up/locking pin is 1/4''.
at one time i had the cat tools to do that work,but now i just use a 1/4 drill bit,you need 2 of them,theres a place in the front of the engine to put a pin,and then a pin goes into the pump.
a regular puller works fine on the gear,cat and cummins both have that flat plate puller,the reason is on some trucks you can pop the grear off without removing the radiator,if you have the flat plate puller.
I always advance the timing when i replace the pump,it helps with power and economy.
woody,i advanced the timing on the FC i sold you.

NHBill,the small lines coming off your pump are just to direct any leakage onto the ground,they are easy to replace,and the engine will be just as happy without the lines.
if the line that hooks to the "T" valve is leaking then the "T" valve itself is not closed or just plain bad. you can replace the T valve too,just unscrew it . no bleeding required when you replace it.
just remember,anytime you work on the fuel system you need to keep it clean,wash it before you start,get all the dirt and grunge off.
Most leaks in a pump any of you guys can fix,its just gaskets and seals,the pump itself is almost bullet proof,kinda like the 3208 engine!
email me at randy@randydupree.com only.

Randy Dupree
2000 LXI 43
Port St Joe Fl.

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Old 02-25-2008
Bill Pape's Avatar
Bill Pape Bill Pape is offline
Join Date: Jan 2008
Location: Commerce
Posts: 11,547

Bill, you ask lots of good questions,

If you have diesel fuel dripping on the engine, it can find its way to the exhaust headers, this is not a good situation.
Each of the three little black drain tubes are hard to identify, but each has a purpose.
One is the "T" valve used to purge or burp the air out of the system.
T valve should be closed, and not leaking.
The second tube is the dry well under the solenoid fuel shut off value.
No fuel should be present here or leaking. This can be repaired from the top of the pump.
The third drain tube in for the front seal on the pump, if this is leaking the pump must be removed. Then repaired, replaced or rebuilt.

Other leaks could be the fuel injection lines,they may be loose or cracked.
You stated the by-pass hose is weak , this must be replaced, a high % of fuel returns to the fuel tank.
A higher probability for a leak is the throttle rod seal, this can be repaired with out removing the pump. Here is the write up in the files;

Wanderlodge Owners Group > Links, Files, Old Yahoo Forum Database and Downloads > Manuals and Files Stored in This Forums Software DATABASE > Index of Downloaded Manuals and Files in Forums Software Database >FILES & DIRECTORIES > 3208 THROTTLE ROD SEAL/

Caterpillar 3208 Throttle Rod Seal Replacement

A 3208 defective throttle rod seal may leak fuel or suck air or both.

Looking into the doghouse:
Fuel leakage may or may not be visible,
Look for weeping around throttle seal, fuel vapors collecting on the left
side of pump and injector lines, then collecting dirt and a greasy film,
more so than the right side of engine.
There may be a hint of diesel fumes when driving and engine hot.
There may be a visible pooling of fuel in the valley

Stalling when sucking air:
Usually after exiting an off ramp, decelerating.
After a climb under load & decelerating, could have white smoke, rough idle.
The 3208 will usually restart, in a sever condition, bleeding the lines may be necessary.

Miths: Caused by Ultra low Sulfur Fuel, high fuel pressure, or low fuel pressure.
My experience tells me, that all the old 3208 throttle rod seals need replaced .
They are old, dried out , cracked , warn, and have lost their elasticity.
They are leaking now or will be leaking soon.

================================================== ==

Parts Lists Throttle Rod Repair

2W-4037 Lip Seal
2D-6392 O Ring rear drain housing bolt
3J-7354 O ring rear plug
9L-7630 Intake manifold Gaskets (2)
4N-0556 Rear housing Gasket
8M-8157 O ring under rear housing
8M-5260 O ring under rear housing

================================================== ==

I am not an experienced Diesel Mechanic, But I was able to
successfully replace the throttle rod seal. So, it is your choice
and your responsibility, if you want to try this repair.
This has worked for me and several other 3208 owners.

The throttle rod seal can be replaced with a few common hand tools.
A 3/8 socket set and a few open ended wrenches.
The turbo does not need to be removed. Just start taking
out bolts and removing parts that are in the way,
Leave the Power Steering Reservoir attached to its mounting bracket.
But remove all bolts from the bracket and tie it up to the
doghouse hinge.
Remove the air filter, box and intake manifold,
Or remove the turbo tubes and the intake manifold.
A few injector fuel lines will need to be removed.
There are eight bolts in the manifold. The far right forward bolt
under the injection pump will back out and stop at the injection pump.
There is a slot in the manifold to slide the whole part out and up.
Stuff shop towels into the intakes , they can swallow a lot
of debris and hardware.
Once the rear injection pump cover is exposed, drain the fuel
out of the rear drain plug.
Be ready with more paper or shop towels , there is at least a
quart of fuel that will drain.
This is a good time to clean this area of all dirt,
use brake cleaner fluid, This will help in keeping debris out of the injection pump.
Remove the cable linkage, and mark the mounting holes.
No changes in linkage adjustments should be necessary.
Now it is time to remove the rear cover. Seven long bolts,
note the different lengths, and the one with an "O" ring seal.
There are two more bolts that are into the block.
Gently remove the cover up about an 1/8 inch and out.
There are several springs.
They will not fly out , Again just note where and how it replace
them if necessary. Next the throttle rod can be removed,
then examine the seal, bushing, and the rod for wear.
The throttle rod may be worn or egg shaped and the cover housing
could also be warn. Carefully tap or pull out the Lip Seal.
I chose to clean the rod with very fine steel wool,
replace the seal, add a small amount of lube to the shaft and reinstall.
Tap in the new seal with a soft hammer or block of wood.
After re-installation use the hand prime pump or
the electric fuel pump to fill the injection pump, and
bleed air out of a few injector lines..
When starting for the first time have a plate or flat piece
of plywood handy to block the intake to stop the engine from a
possible run away.
After the repair and after a test run , there is still fuel
hiding under the injection pump. So, do not panic, Yet.
Just keep drying it out with more paper towels , or try blowing
with compressed air under the forward side of the pump.
Hopefully there are no leaks. Good Luck.

Fuel leak in the Valley

Rear Cover Removed

Intake manifold and Rear Cover

Bill Pape
Turn on a fan get lots of ventilation and use a solvent to clean the top of the engine, fuel lines, & injection pump, to try to locate the leaks, there may be more than one leak, solvent such as brake cleaner or carb cleaner is very flamable..... need lots of fresh air ventilation on the cold engine.

If you are removing parts to repair seals on the injection pump , this is also a good time, (while you are into there) to adjust the valves, the doghouse and valve covers need to be removed. The Valve adjust may not be as critical , but this should be checked eventually, since it seems to be an unknown. This procedure should be in the engine operators manual.
This is about the same as most all valve adjustment procedures, really not that difficult. Cat dealer parts people will print most any picture , you will get a better idea, if all of this is inside your skill level,

If you own and use a 3/8 socket set and associated open end and box wrenches , this is possible for the back yard mechanic.
Randy has also made good pointers, and Yep keep it clean. No dirt into
the system, the final filter is 2 Micron
Bill & Patty
1988 FC, Silver Edition
Commerce, Michigan
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Old 02-25-2008
tjseitz tjseitz is offline
Senior Member
Join Date: Dec 2007
Location: Alpharetta
Posts: 96

NH Bill. If you have leaking fuel. IMO. you need to get it stopped from leaking.

Randy & Bill P. have given some good advice. Check the easy stuff first and you might get lucky and just have something loose or a bad "T" valve.I have replaced seals and gaskets on the I.pump with good results. BUT!! As Randy and Bill P. said. If you go into the pump...Make sure it is CLEAN!!! and STAYS CLEAN!!!! good luck. Tom
Tom Seitz birdless (90 SP sold) Alpharetta GA.
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Old 02-26-2008
tjseitz tjseitz is offline
Senior Member
Join Date: Dec 2007
Location: Alpharetta
Posts: 96

Bill, When I was working on mine. I started with a good degreaser and a hose up on top of the engine. Then when i got all the big stuff off and it was dry. I then when to Brake clean and an air hose to blow it off. What ever you use will be fine its just that a good brake clean or the like will clean fast and dry fast and leave No residue. With just degreaser and water everything will still be wet and soggy and wanting to run IN anything you open up. Hope this helps. As far as the ins. No help here havent done any of that. But I know that Stephen B. carries the stuf you need to do the job. Maybe he will jump in. Tom
Tom Seitz birdless (90 SP sold) Alpharetta GA.
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Old 05-07-2014
Mustang88's Avatar
Mustang88 Mustang88 is offline
Senior Member
Join Date: Jun 2012
Location: Lumby
Posts: 437

Trying to cure a fuel leak in the valley! I have cleaning everything up as per all of the advice provided here.

When I removed the Governor housing there were 2 o-ring seals (one was yellow - maybe homemade?). Looking at the Cat diagram they do not show any seals under the Governor - but I did locate one using the part numbers listed above (8M-5260, think that was the one), but the other 8M part number shows as a seal for elsewhere, not related. The Cat diagram show a dowel on the bottom - I have ordered the dowel - but not sure cover can be re-installed with the pump on the engine block if the dowel is in place. Is anyone familiar with the dowel I am referring to - can I leave it out (as was the case when I took things apart) and replace with the o-ring seal listed.

Thanks for the great directions and photos Bill, made this task much easier - but it still takes me much longer than it probably should!
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Kevin Barnett
Lumby, BC, Canada
1979 FC35SB
the (SLO-CAN) :
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Old 05-07-2014
steve in Texas steve in Texas is offline
Junior Member
Join Date: Oct 2010
Location: Jasper
Posts: 22
Default 3208 throttle seal repair

My recollection of the CAT manual was to run the valves after the 1st 3 months or 1800 miles; whichever happens first. Mine had been over 70,000 miles and had never been performed. Out of 16, 10 were out. It was like I added a turbo...fuel economy increased over 30%, not to mention the power.
Steve Seale
Jasper, Texas
'77 35FC
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Old 05-19-2014
Mustang88's Avatar
Mustang88 Mustang88 is offline
Senior Member
Join Date: Jun 2012
Location: Lumby
Posts: 437
Default It's Dry in the Valley!

Well, finally finished the throttle seal replacement and no more fuel in the valley!

All seals were as specified by Bill in earlier posts! Got it all nicely bled and cleaned up!

But now my RPM gauge is misreading - sits at zero at idle. Appears to be off by about 6-800 rpm. Bad ground - I was working on wiring previously?
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Kevin Barnett
Lumby, BC, Canada
1979 FC35SB
the (SLO-CAN) :
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Old 12-02-2014
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biobug biobug is offline
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Join Date: Jul 2013
Location: Hood River
Posts: 1,759

Ok. Now I have an injection system leak ending up in the valley. I cleaned up the engine early this year and there was some fuel/oil . Now it is there again but it is coming from the Injection Lines going into the Heads . There is dirt and fuel/oil around 4 line connectors .I have not tried to tighten then yet. I am thinking that the ones that are leaking are the ones easiest to loosen and possibly were to get air out of the fuel lines before us. I know there are o rings on the inside connectors to the injectors under the valve covers but I don't remember any on the injector tube connectors where they pass thru to the injectors. It is a place to start anyway. Suggestions?
John Alley
Hood River, Oregon
1992 Wanderlodge 36SP

"There comes a time in a mans life where he must take the bull by the tail,, and face the situation."
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