rear main seal upgrade


New Member
my rear main seal is leaking badly and I was going to replace this weekend and I heard about a neoprene seal upgrade. I was wondering where I could get these and does it go right in like a stock one. I'm on a tight budget and my little Monza makes it very difficult to pull the motor, so if any machining is needed I want to know before I start tearing it apart. thanks for any information
should be able to pick it up in any parts shop. New oil pan gasket. No machining - can be done on your back with engine in the car - well in a G-Body don't know if you can drop the oil pan in your ride.

Make sure it is in the right way.
Let's throw a nail in this thread.

I remember some time ago a discussion about the neoprene seal scoring the carnkshaft over time.

I used the factory rope seal when I did mine, which probably explains why it still leaks a little.

I think it's a 50/50 split on which one to use.
I've had no problems with the neoprene but I have owned 2 h bodys. Once the car is up the k member can be removed and you have full access to the botom of the engine. You may have to disconnect the drag link too but you don't have to remove the engine.
I will try to find a neoprene seal and another oil pan gasket tomorrow, I got the last one at all the auto parts stores yesterday. I can find the 20 bolt pan gasket just about any where but I am running the 14 bolt pan so it a little difficult to find. luckily I can take off the pan with little effort, I changed the pan gasket today cause thats where I thought the leak was coming from,manwas I pissed to find out it wasn't. but thanks everybody for your help, hopefuly have the multi-colored primer beast back on the road in a day or two
replaced my rear main seal about 7 months ago, and no problems since. I used the neoprene seal however did not use the straight side seals provided, instead used silicone. This was the second time it was replaced. the first time I paid someone to replace it (removing the original rope style seal) and it was replaced with a neoprene style seal using silicone instead of the straight side seals provided. after the paid job was completed and I got the car back it began leaking again within a few months. uhhhh!

when I replaced it myself (the 2nd time) I used a fel-pro neoprene rear seal with silicione. after reding several threads on replacing the seal I made sure to clean the rear main cap extremely well, removing all the old silicone and residue. furthermore after installing the seal and silicone and bolting her back up i let the veh sit over night to allow the silicone to cure before even starting the car. I have had no problems since, very happy! IMO the step of allowing the silicone to cure overnight is what made the difference.

if you do a search I'm sure you can find the thread. Good luck!
Yeah. Post a picture. My first car was a 79 Sunbird with a Buick v6. Fun car. Made me want a T Turbo even more. Memories...
here is a couple pics of my Mighty Monza keep in mind I just finished the drive line a just started working on the body
pass. side

the front while was working on it

driver side

Its fun as hell driving it around like this,I get so many dirty looks from everybody especially the mustangs and "F" bodies behind me
Not bad but you need to upgrade to 5 lug. Have you been to Good site and you can find the info for the upgrade there. I found when you go over 100 the stock brakes suck. It also gives you more options on wheel and tire combos. I had the same rims on mine. Looks familuar.
Its already a 5 lug in the rear, I haven't made up my mind on using the s10 spindles or using aerospace brakes. The turbo is going to be added alittle later on, I'm still collecting parts and tying to decide how I want to do it. for starters I have pretty much no room for a stock location GN turbo setup, but eventually it will be boosted.
Ok, I'm blind BTW. LOL At the very least do the G body spindle but the S10 dual piston is a great idea. What gear do you have in it? I have a set of 3.42 7 5/8" if you're interested.
charlief1 thanks for the offer of gears but I have already modified a set 3.73 to fit, but the S10 set up I was talking about was the spindles they are much closer to the "H" body spindles. I have seen the "G" body spindles but it throws the steering geometry off to much. Believe me I don't like the 4 lug in the front or the idea of my calipers being held on by little pins, I'm going to do something about it very soon
S 10 is a metric chasis and uses the same spindles as the G body. The later blazer spindles have the dual piston calipers but the spindle is a direct bolt on to the G body. Very little difference.
I'm not to sure but last time I looked it up the arm that the steering hooked up to on a "G" body was longer than a S10 but then again I saw that awhile ago and could be wrong, it might have been an "A" body Monte Carlo spindle that the site was talking about. but I didn't know about the 2 piston calipes till this thread so thats more food for thought, is there a thread on here about swaping over to thelater blazer spindles?
My dad bought me a 75 Monza for my first car. 350 4 barrel with a 4 speed. Totalled it in 3 months. My second was a 75 Monza with a 4.3 V8 automatic. Love those cars. You still see them at the dragstrip from time to time.
Several threads on converting to bigger brakes using many different spindles. You may have to do a few searches but they're on here.