1966 Monza 110 leaking diff oil again

[ed farley]

Hello,

I have been working on a 1966 Monza convertible, 110, 4 speed car for over two years. A little about the car: the diff and trans are 1966, but I had a rebuilt 110 (LM) engine put into the car almost two years ago. I have been troubleshooting many issues since.

1. diff issue. I replaced the input shaft seal and c clip, slipped in the input shaft, changed the gear lube (80W) in the diff and transmission, and married the diff/transmission to the engine. Installed the engine assembly back to the body; synced carbs, timing, etc. and took it out for a short drive. after about 25 miles or so of testing, I noticed a bit of oil under the car and could see drips coming off the diff bell housing section. It was definitely gear lube... thick and smelled of gear oil.

I did replace the clutch plate and have the new -non rivet- flywheel, so I did not want the gear oil to get all over these new parts. I ordered another new seal and c clip and also ordered a new input shaft, thinking that this might be it too.

As you can imagine, I drove into the garage last night after a nice run and now have gear oil on the floor and drops on the bellhousing at the bottom AGAIN, and I only have about 40 miles on it. I used a sealant (RTV) on the seal too...

I am new to Corvair's, but not new to classic cars, as I have several other vehicles (V8's :)). I consider myself to have okay skills and have been following all the advice from sites like this, the AM, and many other books I have.

I checked the diff shaft area and there are no cracks...there may be some small groves..

2. missfire on passenger side....this is a long story....I had carbs rebuilt for the new engine...but over the course of time found that these were not rebuilt at all; I have since had a different Corvair parts dealer send me another set of rebuilt carbs. All the issues I had with the previous carbs are gone, but now the passenger side of the car is missing (can tell through exhaust; drivers side smooth; passenger side missing at idle, smooths out on accel, but missing at constant speed). I have less than 125 miles on the rebuilt engine/heads.

I checked all the spark plugs, and they look good; yes, the idle mixture screw works and the car will die if I put it all the way in...

I plan to switch the carbs to see if the issue follows the carburetor.

I have the timing at 14deg; the dwell is 30. I synced the carbs and have the same draw (based on the vacuum device that can be put on the carbs one at a time).

I know I mixed two different topics here...but these are the ones that are plaguing me now.

Thanks, Ed

[ed farley]

UPDATE:

I figured out the missing issue on the passenger side...bone head mistake. I did not have the nuts on the carb base tightened down enough and was getting a vacuum leak..no more issue.

So now onto the diff leak.

Ed

[ed farley]

UPDATE:

I figured out the missing issue on the passenger side...bone head mistake. I did not have the nuts on the carb base tightened down enough and was getting a vacuum leak..no more issue.

So now onto the diff leak.

Ed

[Rick4130]

I’ve dealt with diff leaks, and I find that section of the car to be a little primitive. The seals that press in by the axles can’t really be enough to hold back all that fluid, plus they get “compromised” when inserting the axle yokes. Have a few of those handy and replace whenever you are in there. I’ve had leaks at the filler plug too, and also dripping out by the side adjusters… it’s a big flat edge o-ring that is in there….

It’s frustrating but safely jack it up and get comfy with a good flashlight… spend some time just staring at it and maybe you can see right where it’s coming from.

Nice to hear about that easy vacuum leak too!

[Dennis66]

I ordered another new seal and c clip and also ordered a new input shaft,

I checked the diff shaft area and there are no cracks...there may be some small groves..

Better definition of "diff shaft area" Throw out bearing tube?

Questions I have to ask:
Verify that transaxle is not overfilled? BTW, did you use GL4, or GL5? GL4 is what you are supposed to have as GL5 can attack the brass syncros. SHOULDN'T HAVE ANYTHING TO DO WITH LEAKING.

Have you checked the differential vent to make sure it is breathing correctly?

Verify thst you have th ecorrect input shaft? (just because it's identical to the first one doesn't mean THAT one was correct to begin with. While I don't recall the specifics, there were at least 3 different input shafts tht I know of. IIRC, they MAY have been: 1963 and back, 1964-1965, and 1966. There may be others (?). I believe the 1966 and newer are a bit longer that the 64-65

I Take it from your wording that you have already removed the engine / transaxle a second time?
What does an inspection of the seal look like?
Do you have a set of V blocks to check for runout on the input shaft? (new doesn't always mean good.)
What was your procedure for installing the seal? (I use a deep socket that barely fits in the T.O. bearing shaft.
Positive there are no cracks in the T.O. bearing shaft (tube / hub / whatever you want to call it)
What was your procedure for mating the transaxle to the engine? Use guide pins made from 3/8 bolts?
Finally, condition of pilot bearing (have to assume it's new / good because of everything else mentioned, but still have to ask.
It's going to boil down to careful inspection to see where it's wet with gear lube when you first open things up. Inside the T.O. tube? That points directly to seal or shaft problem

[66vairguy]

Good comments, especially the vent.

The input shaft from the clutch disk goes through the throwout bearing support tube that contains the shaft seal and "C" clip. BTW that "C" clip DOES NOT HOLD THE SEAL IN - it is just there to keep the input shaft from damaging the seal while the input shaft flops around until transaxle is mated to bell housing and clutch. Some make the mistake of trying to pounding that "C" clip up against the seal - a NO NO. IF there are rub makes on the input shaft at the "C" clip area, then something is out of round.

Always put a little chassis grease on new seal lips that touch the input shaft - otherwise the seal will overheat fast before lube gets to the.

Also - if the lube leaks out of the throwout bearing tube it gets all over everything (eventually). What I wonder is if the bellhousing seal is leaking. Yes motor oil, not transaxle lube - just asking.

Some have had the transaxle lube leak when parked on a steep hill (front of car higher). Dropping the lube level a 1/2" is reported to fix this.

Just my

[ed farley]

Thank you all for the helpful comments:)

The new input shaft was ordered from Clarks and was for a 1966 diff/transmission...unfortunately I did not measure it before installing....

I used SAE 80W-90 GL5 gear oil

I have not removed the engine assembly yet....that is the plan, so I will check the vent and the amount of gear oil in the car. I have it on the lift now...but will need to order the seal and c clip again.

I just asked the engine builder if the pilot bushing was replaced when the engine was rebuilt. I did test fit the input shaft end with the pilot bushing and it fit very good no wiggling around.

The last time this happened, the gear oil was in the base of the housing...no oil on the clutch or flywheel.

When I installed the seal, I used a deep socket to install the seal...I don't remember how tight I placed the c -clip to the seal..may have put it right on the seal.

I had the engine on one flat surface with wheels and the diff/trans on another flat surface with wheels. I made sure everything was level and that the input shaft slide into the clutch and pilot bushing with just a little bit of adjusting...not binding.. I thought I did something wrong the first time I did this (bound it up a bit), so made sure that everything married smoothly.

It is going to be a few days before I can update on this, as I have other tasks to do, but will let you all know what I see under the car (flashlight) and will check the oil level....

I am curious, if I have the level too high (or find that the vent is plugged), will removing some of the oil/get vent working fix this? or do I need to go through the process of removing the engine assembly and replacing the seal etc.

Thanks, Ed

[jimbrandberg]

Where did you put RTV on the input shaft seal?
I bet an input shaft wasn't cheap.
The collar where the input shaft seal goes and the throwout bearing rides on isn't cracked or anything is it?
About all the split washer thing after the seal does is protect the seal during assembly.
I'm sorry I don't have much, just trying to reason through it.

[Dennis66]

FYI, there should be no reason to replace the "C" washer if you need to replace the seal.

[66vairguy]

FYI, there should be no reason to replace the "C" washer if you need to replace the seal.

Correct --- it does nothing once the transaxle is on the engine it just protects the seal during assembly!!! Odd that Ed keeps saying he has replaced it. Why?

Ed, as I already asked --- DID YOU PUT SOME CHASSIS GREASE ON SEAL LIPS!!!!!!! If not that seal was destroyed as soon as the input shaft started turning unless it had lube on it!!!!!!!!!! Same with the crank or H B seals when installed.

I recall the inner part of the throw out bearing tube has a small ridge to keep the "C" washer from contacting the seal. If you don't get the seal past that ridge IT WILL LEAK.

Good luck.

[ed farley]

Hello 66vairguy,

I recall putting lube on the seal before installing the input shaft. I did replace the split ring (I looked up the correct name) from advice given during my review of this procedure.

One question I have...I watched a video of this procedure on Youtube (Dave M.), and in that video, Dave only drives the seal to the ridge in the clutch release bearing shaft...not beyond the ridge. Not sure how it could go beyond that ridge?

According to the chassis shop manual, it says to drive in new seal, open side inward (which I did) using a deep socket. Drive the seal until it bottoms, then install split ring. The seal bottoms at the ridge in the clutch release bearing shaft. I drove the split ring in until it was just touching the seal...similar to what I see in figure 1 in the chassis manual for the rear axle, and what others have shown on Youtube for this procedure.

I am planning to remove the engine assembly, disconnect the diff/trans from the engine and do a better inspection of what I see. I also plan to replace the gear oil as I may have mistakenly put in GL5 and not GL4......It is going to be a few days before I get to that, but will keep you posted on what I find.

Thanks, Ed

[Dennis66]

Lessons learned the hard way:
* Careful attention to installing input shaft seal.
* Careful mating engine to transmission
* Use sealer on threads of flywheel bolts
* Use ALL SIX flywheel bolts (when I was a young, dumb kid, I dinged one hole for the flywheel bolt. I figured "5 should be good enough". The trail of oil in the road and slipping clutch (brand new disc) after a half a block was a lesson learned.
Yes, I have been guilty of all the above.
I actually installed on engine by plugging the input shaft into the clutch, sliding the front end into the differential, and feeding the whole thing in by sliding the input shaft in. Yes, it destroyed the seal, Yes, it destroyed the clutch disc.
52 years later, I've learned a few things.

[ed farley]

Yes, I have learned quite a few lessons while restoring the 66. My dad had a 62 Corvair when I was young....so I thought it would be fun to get a Corvair to work on. I live in Juneau, AK, and there was one for sale; 66 Monza convertible 110. (only one it town that runs!) It had a '62 engine in it, but it ran fine, so I wasn't planning to do anything with the drive train.

I changed the spark plugs and did not notice that I had one of the spark plug wires close to the passenger carb. Started the car and had immediate high RPM...so what do you do when that happens? hit the gas of course hoping to drop down the idle, and instead had it drastically increased rpm....I shut the motor off and discovered the spark plug wire underneath the passenger throttle...holding it open...good grief.

Fixed that, went for a drive and suddenly heard the dreaded flywheel ... okay when clutch in...not okay when clutch out...so obviously a rivet had given way during the high rpm situation.

I thought, if I'm going to replace the flywheel, clutch, etc...why not go ahead and have a 110 built for it...so I did. As you can imagine; new rebuilt engine, shipped to Juneau, new flywheel, clutch, etc was expensive, but I am already underwater with the car, and I do like it, so I'm okay with that.

My next experience was getting the rebuilt carbs synched. Who knew that if you get rebuilt carbs that the person rebuilding them would not set the floats, or have floats that were bent in the middle section meaning one float was further down that the other. I did not discover this until after MANY trial runs. I had fuel pouring out the base of one of the carbs no matter what I did (VERY Dangerous). I decided to open up the carbs to see what was what and discovered that the floats were not adjusted along with the other float situation. I fixed all that put them back on the car, but for the life of me could not get these carbs to work right...so I had two more carbs rebuilt by more reputable place...these carbs are working great now (test drive yesterday after I fixed the vacuum leak).

Then the leaking gear oil. this is the second time this has happened with just about 40 miles on the new seal each time. I hope I figure this out in the next week or so.

All this to say...I have had the car for two years and have not put 100 miles on it yet. This will be the 3rd time I will drop the engine.

While I am getting better at diagnosing issues...I just want to drive the car:)

Thanks, Ed

[66vairguy]

Hello 66vairguy,

One question I have...I watched a video of this procedure on Youtube (Dave M.), and in that video, Dave only drives the seal to the ridge in the clutch release bearing shaft...not beyond the ridge. Not sure how it could go beyond that ridge?

According to the chassis shop manual, it says to drive in new seal, open side inward (which I did) using a deep socket. Drive the seal until it bottoms, then install split ring. The seal bottoms at the ridge in the clutch release bearing shaft. I drove the split ring in until it was just touching the seal...similar to what I see in figure 1 in the chassis manual for the rear axle, and what others have shown on Youtube for this procedure.

Thanks, Ed

Ed --- Look at the 65 shop manual Fig. 1 on page 4-2. You'll need a magnifier, but there are TWO stops (ridges). One for the seal and a slightly more prominent edge that the "split ring" washer seats against. The seals have a film on the housing to act as a sealer, but I also put a thin film or RTV on the outer edge of the seal housing.

Oh! Note the Clarks reproduction clutch bearing support tube was designed to hold TWO seals. Is yours original or the Clark's repro???

Good luck with the problem.

[Dennis66]

Noticed that you DID have a '62 engine, but now have a "110". Did the 110 come with a bell housing? Or are you using the bellhousing from the '62. THEY ARE DIFFERENT. A late (110 or 164 CID bellhousing is casting 3832176 while the early ('62 145CID is # 6256583. This could caus seal issues on the CRANKSHAFT seal. Might be a good idea to identify and post your bell housing number.
Also are you using a flat flywheel or a stepped flywheel (clutch area is recessed) Flat flywheel has flat clutch spring fingers while stepped has bent fingers. Dennis