What's the REAL story with Bravo XR's?

[J.T.]

Mine were older drives. So you may be on to something with the way they're making new ones.

Would make you sick to think of new drives being weak compared to what was made in years past.

After one of the 2 new sets I had cryo treated back in
07' started to chunk out, and since I've lost all confidence in
new XR gears, I ended up putting one of the old set that I took
out of one of the drives back in.....and for 2 years now, they've been fine.

[C_Spray]

Everyone's missing the REAL point. A few years back, Fred Kiekhafer himself pointed out (in print) that the Bravo was originally intended for just over 300 hp. In the ensuing years, numerous band-aids and improvements have been made to increase the drive's strength, but the bottom line is, in almost all performance applications, the Bravo is being used for far more power than it was ever intended to handle. That's why when one problem is fixed, it breaks at the next weakest point. Mercury never designed a drive to handle go-fast power over 500 hp until the NXT. In the meantime, no one was interested in installing an overkill $25,000 #6 drive.

In short, there should have been a "Charlie" drive to handle 500-800 horsepower, but Mercury Racing didn't have the $$, and Mercury Marine didn't need the capacity. The net result is that Bravo owners have served as the development fleet for Mercury, spending countless hours and dollars on both successful and insuccessful upgrades. The bottom line is that the Bravo is simply too small by about 20%. It's like using a Pinto transmission in your Corvette. It's inexpensive, it's low drag, and it will work most of the time, but there is no room for error.

[CRC]

Merc has a long history of making changes to save money. Sometimes it works out, a lot of times it doesn't and they go back to the original. It wouldn't surprise me at all if the new gears are being made somewhere else or with a new process..

Wow, and I was a little concerned because I bought a brand new old style XR upper without the sloped back housing. So now maybe I got a better drive?????

[Bad Idea Baja]

Wow, and I was a little concerned because I bought a brand new old style XR upper without the sloped back housing. So now maybe I got a better drive?????

Probably not, but here is to wishful thinking.

[HaxbySpeed]

The newer sloped back ones are shim-able allowing for closer tolerances on set up..

[Bad Idea Baja]

The newer sloped back ones are shim-able allowing for closer tolerances on set up..

What are you talking about? Every Bravo I've had apart was shimable. Is there something I'm missing on with the slopebacks?
Hey that sounds like the making of a racial slur.

[J.T.]

What are you talking about? Every Bravo I've had apart was shimable. Is there something I'm missing on with the slopebacks?
Hey that sounds like the making of a racial slur.

The last of the old style and the new styles ( slope back) have shims
behind the pinion

item # 40 in the pic.

http://www.mercruiserparts.com/Show_...FXZ%2DDrive%29

The complete new upper I bought in the fall of 05' was this way.

[Skullkrusher]

Peter,
I don't forsee you getting any help from Merc. From vapor lock on 502's, to water reversion on HP 500's, computer probs w/ 700's etc. etc. They come up with a fix, but it is up to the owner to eat the cost. In short the consumer is Merc's R&D department. I'm sure the dictionaries at their corporate offices show "customer" and "sucker" as synonyms.

[LAKE EFFECT]

Everyone's missing the REAL point. A few years back, Fred Kiekhafer himself pointed out (in print) that the Bravo was originally intended for just over 300 hp. In the ensuing years, numerous band-aids and improvements have been made to increase the drive's strength, but the bottom line is, in almost all performance applications, the Bravo is being used for far more power than it was ever intended to handle. That's why when one problem is fixed, it breaks at the next weakest point. Mercury never designed a drive to handle go-fast power over 500 hp until the NXT. In the meantime, no one was interested in installing an overkill $25,000 #6 drive.

In short, there should have been a "Charlie" drive to handle 500-800 horsepower, but Mercury Racing didn't have the $$, and Mercury Marine didn't need the capacity. The net result is that Bravo owners have served as the development fleet for Mercury, spending countless hours and dollars on both successful and insuccessful upgrades. The bottom line is that the Bravo is simply too small by about 20%. It's like using a Pinto transmission in your Corvette. It's inexpensive, it's low drag, and it will work most of the time, but there is no room for error.

I hear what your saying and agree with you mostly. The problem I'm *****ing about is that the early XR gears appeared to be made right and didnt break teeth off, and then the gear was changed, prices raised and quality got worse. I wish someone in the aftermarket would come up with a gear set that is worth the $1600 Merc charges.

The Bravo is an overstressed drive in most applications they are put in, but choices are limited. IMO Merc didnt need to design a entire new drive with the NXT 1. They had the TRS, #3A and #5 they could of worked off of. The parts and tooling were already available. A redesigned lower unit on any of those drives that accepts the Bravo/Maximus props and they would of had an affordable middle of the road drive. Isnt the NXT 1 drive priced close to the #6? That doesnt help the consumer.

Oh and by the way, the Pinto came with a C4 trans. Yes a small trans, but built right and put behind some HP, it can easily support 9 and 10 second ET's and usually last a race season. Kind of sounds like, well a, Bravo..

LE

[C_Spray]

This is a thread that Mercury would probably prefer JD Power did NOT see...

[HaxbySpeed]

A while back Merc changed the XR gears to one's with a thicker floor. Apparently they used to have a lot of failures in that area. Does anyone know if these are the ones that are having all the issues?

[CRC]

Probably not, but here is to wishful thinking.

Damn, oh well....

[J.T.]

A while back Merc changed the XR gears to one's with a thicker floor. Apparently they used to have a lot of failures in that area. Does anyone know if these are the ones that are having all the issues?

They changed the helical style gears to thicker floors when they came out with the X gears


http://www.go-fast.com/mercruiser_bravo_sterndrives.htm

To my knowledge, the XR gears have all been of the same
design.

[PARADOX]

I'm a little confused?? You started the thread saying pin bearing, then started calling the part a pin gear?

You are talking about the upper cap needle bearing that supports the upper part of the clutch shaft right? part #31-843240.

I put on a set of early XR's that came with the std Bravo cap, not the later cap that was redesigned(fin cap). I put on my Max Machine caps from my old drives. These caps use a better and taller bearing, that uses more of the bearing surface of the shaft. I plan on some spring drive maint. pretty soon and will look for any goofy wear on my current clutchshafts, but maybe a better bearing or cap may be in order to ease your mind.

I'm more pissed at Merc with their gear sets. Not only did they raise the price into the atmosphere, but the quality went down the tubes. As mentioned in this thread and on a couple others, the newer gears(3 or so yrs old and newer) no longer wear out and start to pit(as a gear should) but crack and loose teeth, which can destroy a case. IMO thats what Merc should be investigating.

Good Luck,

LE

Sorry.. I guess the correct term is in fact the "niddle bearing" Digs right into the upper driveshaft. I have a sample that I'm taking to the Miami show and will put Merc right on the spot. Will see what they say.

[ROGUE]

Love my 88's. Even the cases were fatter back then.

[2112]

Wouldn't surprise me a bit if they were made in China now.

I bought a new ITS input shaft assembly this year. It was made in Italy.

.

[HTMike]

I had a box stock XR Upper ( not even an upgraded top cap ) on a standard length sportmaster lower in my 1100 hp Procharged HTM. Has to have 150 hours on it now with the new owner and no issues yet. I used to do 20 - 120 MPH pulls all the time.

[HTMike]

Pic of said drive

[Hammer01]

A while back Merc changed the XR gears to one's with a thicker floor. Apparently they used to have a lot of failures in that area. Does anyone know if these are the ones that are having all the issues?

Actually in 01/02 they also played around with the xc bravo drive (i believe that is what it was called) which was the xr with angled teeth in the gears rather than a more standard 90 degree combination. I only know this because my 38 donzi popped an upper with only around 30 hours and my cert mercruiser mech said the XC drive was junk and the teeth were changed in the upper and lower gear set to make for smoother and quieter shifting not realizing it compromised (obviously) the dependability and durability. When he reordered my gear sets (I went ahead and did both), he ordered the xr gears and never had a problem in 400 hours after that!!! Driver error can be blamed for a lot of the issues being discussed because I have friends with almost 600 hours on their bravos and bravo xr's with no problems. A lot has to do with the torque these days also.

[ROGUE]

The last of the old style and the new styles ( slope back) have shims
behind the pinion

item # 40 in the pic.

http://www.mercruiserparts.com/Show_...FXZ%2DDrive%29

The complete new upper I bought in the fall of 05' was this way.

All of them can be shimmed behind the pinion if needed.