It will work. That's all I've ever used. That bearing is for an XR, merc calls their bearing a "red dot"' for an XR. It will still work for a standard bravo.

Sierra's GB for 1997 and back for Merc is 18-2100 and you can put them either way ( backwards).

Next 1998 and up Merc takes GB 18- 21005 and do not put this one in backwards - the inner portion end is a tad shorter on the end - it shaved down compared to the older GB - I think around .030 This needs to be facing out when you install it. Both of these GB are greaseable.

Sierra 18-21001 is the non greaseable (just like merc one) for anything 1997 & back. Merc started non greaseable GB in 2008 and so did Volvo penta in late 2007. FYI.

next for 1998 and up - alpha's Gen II, Bravo, X / XR / XZ - Sierra really recommends 18-21006 - this is a non greaseable GB. if I recall correctly Sierra's GB is Link Belt or GKN currently - I forgot. Mallory Marine carries the SKF - GB inwhich is good also.

The consensus seems to be it will work.

I see that the inner portion is shorter on the original Merc one I pulled out and that is where my concern is coming from. If as you say (which I don't doubt) the 18-21005 needs to be put back in a certain direction how does the 18-2100 which has a longer inner part on both sides not cause any problems?

I re-read your post and it looks like your saying the shorter center needs to be to the outside. If this is the case then the 18-2100 bearing definitely wouldn't be a problem. That makes sense now.

there is a reason for the shorter inner and as why it needs to face outward. These GB are different by design by load and the shorten end is for cleanance as to when trimmed fully & full left to right turns not to produce a slight noise. This applies to 1998 and up models from Merc.

the 1997 and back GB the input driveshaft has this clearance already plus the load is different on the bearing than 1998 and up.

We have probably installed 1000 + GB over a course of 24 years. Nobody ever pulls their drive to completely check the condition of the U-joint bellows until after the leak and the deep growl by the GB from water intrusion that has already taken place or the boat owner left the drain plug in during rain storms. Shift cable bellows is a another story just the same but alot easier to check but still nobody checks that either - not to change the subject here.

2001 boat uses 18- 21005 not 18-2100 both greaseable. You can call Sierra on this if by chance anyone thinks i do not know what I'm talking about, no offense on my end. You have to install this bearing 18-21005 correctly. Also you can call mallory Marine and Merc to verify what I'm talking about. We attend all the OEM marine schools and take all the tests and we are very current all the way up to the catalyst systems in these marine motors. FYI & Good luck.

I'm confused now. I have a 98 boat and just ordered the 18-2100 gb. So this bearing will or won't work? It's a bravo 1 drive.

Thanks

I just installed the 2100 on a 98 Model Hammer. It will work. No problems. Just install it with the dot facing out and line your grease hole up with your zerk fitting on the gimbal housing.

Forget all that installing backwards crap just because its easier. If im going to take the time to remove my drive and check everything out, Im putting a whole new bearing in with new race. Just my 02 cents.

Since I asked the questions that probably got you confused I'll give you my conclusion. Can the 18-2100 be used in place of the original for your and my model yr? YES. Is it technically the correct gb? NO. Is there a difference between the two (18-2100 & 18-21005)? YES. The difference is the center piece of the bearing is the same on both sides of the 18-2100 which means in theory the drive will not trim out as far because the shaft will bottom out on the gb sooner. Will that 0.030 difference really be noticeable? Don't know. Most people on here seem to say no.

I haven't made up my mind which one I'm going to use yet.

What about the seal I see in the parts fiche? Does that also get changed when changing the gimbal bearing? When pulling the bearing out with a puller, does the seal come out with it? How about the bearing carrier, does that come out with the bearing or stay in? Thanks.

I did not change the seal on mine when changing the bearing. I did have to turn the bearing a little in order to get the puller in between the seal and the bearing though. Then just put it back straight before starting to pull it out. As for as the carrier, If it looks like this pic with the notches on either side of carrier then you can just pivot the bearing where the notches are and pull it out.
http://i1082.photobucket.com/albums/...psa7c377eb.jpg

If it looks like this pic then you will have to use a puller and both the bearing and carrier will come out together.

http://i1082.photobucket.com/albums/...ps9b94f1d7.jpg

Thank "seafordguy" for the pics. He helped me out.

So is this seal not something that usually get's changed out with the gimbal bearing replacement? Anyone? Why wouldn't a guy want to replace it?

had a GB replaced last season,,and they didnt change that seal either,,dont know why ???

There is no "seal" just the bearing and the carrier.

He's talking about the shaft seal that's just beyond the bearing. Can only speak for myself and the reason I didn't change it was it seemed perfectly fine, no wear, still pliable, etc. Seems it's only there to help keep the grease from entering the inside of the boat.

would that seal stop water from coming into the boat if the bellows were to go?

The seal isn't there to keep grease out of the boat. There would need to be a ton of grease in there before it got that far. I believe it is there to keep any water inside the boat from getting to the gimbal, but if the bellows went bad it would help keep the water from entering the boat by slowing it down. Either way if you get water in the bearing it won't last very long. I have change them before, but not everytime. If it looks good and is pliable, just change the bearing.

Sounds reasonable. Thanks

Well i've decided to purchase the tools from Whoya, and get the Sierra bearing. I'll be tackling this job as soon as I get the parts. Is the grease port on the bearing and grease port in the housing obvious to see to align back up upon installation?

Thanks.
Ryan

Not to hijack this thread but I'm doing the same job. I want to replace the bellows while I'm doing the GB. Should I buy a Sierra part for that as well? Anybody have a part#? Also, should I be replacing the water inlet hose too? I recently put a new shift cable and bellows in so I'm not doing that. Thanks

Cloudmaster 321 I usually mark the lube hole in the bearing with a marker & line it up with the hole in the housing which is about 4 or5 oclock position & pound it in. Brwn 234 I don't have a part # but I know you can get a complete kit from sierra that includes water inlet hose, ujoint bellows, exhaust bellows. shift bellows. & bearing. You can get it from any auto parts store that has a sierra book. Randy The part # for a complete kit is 18-2212 I think

if you are replacing the water hose buy the water insert tool its only a few $$ makes get the plastic inserts easy to screw in .

Is there a trick to getting the shaft seal out. Doesn't seem like there is a lot of room to hit it and distort the seal to get out. The machined area this seal sits is almost as big around as the seal?

I did get the gimbal brg out, it was stuck in there pretty good however

For what it's worth, I installed 18-2100 in a 1995 bravo III and it seemed to have a little more u-joint knock at the extremes than before the install. This could be for any number for reasons, but I figured I'd add my experience to the thread. I'm going with 18-21005 for my alpha gen II this weekend.

Hi there,
Hoping BUP or somebody that knows sees this question - BUP said:

"Next 1998 and up Merc takes GB 18- 21005 and do not put this one in backwards - the inner portion end is a tad shorter on the end - it shaved down compared to the older GB - I think around .030 This needs to be facing out when you install it. Both of these GB are greaseable"


I have a 1999 Capri boat with an Alpha One Gen II and while I was away on a trip, my dad (a very good trained mechanic, but not a boat mechanic) thought he would help me out and put a new gimbal bearing (Sierra18- 21005) in for me. I had already purchased it, and we were gonna do the bellows, shift cable, and gimbal bearing install after I got back from the trip. When I got home last night, he had already installed the gimbal bearing. [B] He installed it with the two slots facing inward[ toward the boat/B]. This is the way the service manual says to do it, so he just followed the instructions.
My questions is...is that the proper way? Or are the slots supposed to face outward toward the back? I have searched the web and seen two different opinions about this. So now I am wondering if we need to pull it out. I really appreciate any help you are willing to give.

Sincerely, Willy

Yes I am up here today and see your post brought all this back up. Hey NOT to knock anyone up here but do not install 18-2100 GB in 1998 and newer boats. Sorry guys you are 100 % wrong and do not know the reason. For one I have the SB's from the bearing makers GKN and SKF along with Mercruiser. But I know some will come up and say it works no problem - ok great for now but I guess the companies that make these GB's have no idea and the end user knows way much more than they do.

Anyways what do you need to know.

next all sterndrive manu's went away from a greasable GB. For many reasons. One is the end uyser never greases them anyways. Next water intrusion is a somewhat better for not locking up the bearing up in short order from corrosion. Next many techs and do it yourselfes sometimes have problems lining up the grease holes so when the zerk is greased the bearing internally is not getting greased. The average is the non greasable GB has a longer life in use. Volvo Penta has used a NON Greasabl GB since the latter part of 2006 model year 2007. I have changed less of them in the past 9 years than the greasable ones that are 9 years old - regardless. If I would have to count how many GB I have changed out it at least 1500 if not more maybe 2000 GB's. Just saying. Current bearings use by the manu's are SKF and GKN.

A 3 jaw puller is waste of time - the newer tools on the market pull these bearings in your sleep.

As I noted above, He installed the Sierra 18- 21005 greasable gimbal bearing. Everything is lined up well. But the question I posted above is concerning the fact that he installed it with the two slots facing inward. I keep seeing different opinions about this and am wondering if he installed it backwards or not? Basic question is...Do the two slots face the front of the boat or the back? Service manual seems to indicate the slots go inward toward the boat.

Sorry I finally just seen your PM. I wonder how you were able to get one in. They are full.

Anyways - yes slots need to face inwards, These really are called bearing carrier notches just an FYI.

Thanks so much for your advice. I guess the message got through because I sent it the other way, But the reason I am confused about the install of what direction the bearing carrier notches go is because the Sierra dealer I bought the bearing from is telling me that (His words) "Yes! take it back out, If you leave it that way with the notches facing inward, you will not get proper alignment and blow out a coupler on back of engine. The bearings are slightly tapered inside and outside. You may have a real hard time removing the bearing now because it is wedged in. Do not look at Utube videos or the manual they are backwards. We rebuild hundreds every year."

Those were his words above - So is he just completely misinformed?

it makes no difference either way ..if you put it in with notches facing toward you ..the bearing in the center can be turned to the side and pulled out .that's what the notches are for .I had a bearing place up here that sold just the center bearing only .I have replaced hundreds of these bearings with never an issue

Got to jump in for the last time. Again the newer GB for all 1998 apps and above has it reasons for the change & part # change plus the proper way of installment.

The newer GB on one side ( the center portion center inner race) is .090 shorter in length compared to the other side - this side needs to face out towards the drive. Again one more time it is .090 shorter than the other side of the GB. It is shaved .090 shorter for clearance purposes is the main reason.


Also in 2004 Mercruser had to changed to GKN U-Joint / input shaft assemblies that replaced the Rockwell U-Joint assemblies (NLA) from Rockwall ( I am talking about on the outdrive side here) - These newer assemblies caused interference with that center section of the GB. This also put extra load on the GB. A new bearing was offer that is shaved .090 off compared to the other side. The reason for the new GB and for the shorter side facing outward when installed.

NOW IF YOU HAVE 1997 and BACK APP that still has OEM stock Rockwall U-joint assemblies the 18-2100 will work and can be installed either way.

Next the GKN U-Joint assemblies come black in color the older Rockwall U-Joint assemblies came in non painted grey in color. FYI

Can someone post Mercruiser Service Bulletin 2000-8 up - if I recall that might be the SB that started all of this way back in year 2000 but could be WRONG about the SB #..

If I recall this the first start change of the GB because Some complaints came in from Bravo users of slight noise .Merc followed up and put out Service Bulletin about the change GB for Bravo apps at that timeframe. Then later on came into play for the Alpha apps.

Again this applies to Mercruiser 1998 and above assemblies as they Merc - DECIDED to have this newer GB to be used way back starting 1998 till the grease Jerk was completely removed in 2008..

All current Merc assemblies since 2008 use a non greasable GB and still is installed with the shorter side facing out. Merc does not even sell a greasable GB if I recall correctly. They want you to install the newer one Non greaseable GB then remove the grease jerk and replace it with a plug retrofit.. Good Luck.

Willy I will have to look at the bearing to be 100 % correct. Does your GB have a red painted dot on it. If not what color is it and which way is the dot facing when you installed it. Can U see the dot facing outward ?. Thanks

It has a Black dot on it. And the way it is installed now, the black dot is facing out. Bearing carrier notches are facing in.1999 Alpha One Gen II.

heck all of thinking about it, I am confusing myself. I do not have a GB in my hands. the easiest way to install the newer GB required is the inner race length is shorter. I remember now it is .090 shorter than the other side. The shorter side needs to be facing the drive - outward.

The reasons, the shorter side facing outwards and the correct GB needs to be used because interference will take place with newer style u-joint assembly. This will also put increase load on the GB because the clearance is not there as the U-joint outer assembly comes in contact with the inner race of the gimbal bearing (GB). On top of this load is further increased especially when trimming up and full left and right steering inputs this extra load can cause noise on top of that some owners have reported.

Like I said this really started in 2000 when the Bravo apps changed to the bigger u-joint assemblies used in The X, XZ & XR. these newer U-joint assemblies are call L-18.

I will change my other posts to shorter side of .090 inner race length.

If I recall the dot side is the shorter side that needs to face outwards. Again I will have to look at the bearing to remember correctly. I always look for the shorter length of the center inner race and put that outward. I know that's the correct way. I promise 100 % plus thats a piece of mind knowing I have the shorter inner race side facing outward no matter if the dot was painted on the correct side or not.

next if you are installing a non greaseable GB actually called Perma Lube GB no grease seal is required. If it is installed, you can leave it in if you want to or not. just a FYI for whomever.

So couldnt you just use the newer style non greasable bearing on anything then?

Not sure which I need. One drive is 0F532009 and 0L18700? it has both the same in it now, looks non greasable and if you lay on table one side vs other def is a difference, dot was facing me when looking at it outside boat

There absolutely is a seal it's meant to keep dirt from getting in from the engine side. It really doesn't even have to be replaced although I do replace them since they're only like seven bucks