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MG MGB GT V8 Factory Originals Technical - Hydraulic throwout bearing
|My Hydraulic throwout bearing is shot. The rollers are falling out of the bearing. Question: should I just replace the bearing since that seems to be the only problem? The bearing can be purchased from McLeod Indusrties for ~$70. Has anyone done it? I'd like to hear that the old bearing just twists off and the new one twists on(I wish). The alternative is to purchase a new one for ~$350.00. You can guess what I'd like to do. But, I also don't want to be pulling the engine, to replace the bearing, any time soon because I took a short cut either.|
You should be able to pull the tranny to get to the HTOB without pulling the engine. How many miles on the HTOB?
|McCleod has also improved the HTOB such that it is less likely to leak.|
|I was always worried about using a hydraulic bearing because of the high cost of replacement, but somebody assured me it would last so long that it was worth it. Youíve proven that to not always be the case. As it turned out I took another route and had to change out a standard bearing due to failure. As Carl says, you may not have to pull the motor, but that depends on how your whole setup works. My transmission comes out without pulling the motor; yours may require the motor to come out. I donít use the hydraulic bearing so I canít say if it comes apart so you wonít have to replace the whole thing, but I suspect you will. The only thing I can say to help is that you should investigate the cause of the failure. In my case it was because the clutch fork was binding and causing undue side force on the bearing. That wonít apply to you, but it goes to show that something caused the problem and if you have to pay a second $350 you need to avoid doing it a third time.|
|Webber/McLeod has been bought out by sombody, now that they are sucessful &, I suspect, Red Roberts wants to retire, but they still offer a rebuilding service for the HTOB. I just sent one in for refurbishng & updating to the latest swivel hose connection. Cost is/was $50.00.|
Georges is correct, they can fail, as can almost every part on the car. The one I sent back had a slight leak at the banjo fitting, but was in my blue GT/Rover 4.2 for 230,000 miles & an occasional top off was not a problem.
Most fail because the installer fails to read the instrutions. You must install some kind of pedal stop because you can over-extend the piece, at which point it will blow the seals. This means you have to pull the tranny, at a minimum.
|Carl, I have about 20,000 mile on the car. about 80% is highway driving. The bearing may have had to much constant pressure from the pressure plate fingers. I never re-adjusted the bearing (or checked it out) as the new clutch was getting worn. The initial adjustment recommended was 0.100-0.125 inch clearance between the bearing surface and the fingers. When I checked it out 1 and 1/2 rotations of the bearing was required to have it free from contacting the fingers. I don't know the tread pitch so I can't give a distance.|
My 'B' is a 77 with the Buick 215 and a T5 tranny. I've not tried to figure out a way to remove the tranny without pulling the engine. If my ancient memory serves me correctly the 2 main hurdles are 1)getting the bolts out of the tranny and 2) getting the tranny past the frame?? support bar that is under the tail shaft. There could be other issues as well. Any suggestions for doing it are every much welcomed.
A few years ago, I ran into this same issue with a brand new $280 Mcleod TOB. Turned out that one of the banjo "O"-rings had a tear (from the factory). Thanks to Dan Lagrou, it was repaired but I still had the chore of replacing it by pulling the xsmn (T-5) which can be done without too much trouble. I can't give any positive testimonial for the Mcleod - it cost me a lot in aggravation and effort to repair this brand new and expensive part.
With the current Ford 302 swap, I decided against the TOB and went with a hydraulic slave - if the darn thing leaks it will be replaced in 10 minutes and only cost me $30.
|There are many reason why a HTOB will fail.|
The must common is the input shaft housing misalign, old type conectors. Just to mention a few.
Mcleod has improved their HTOB as Jim stated. I have one that has about 90k miles without any problems, this bearing is one of the new improved.
The bering can be send to Mcloed for rebuild and yes the charge is $50 plus shipping, they will install all of the new improvements.
Steve Carrick solve the problem on the leaks very nicely on the old type bearing.
To removed the trans without pulling the engine it will require to cut the fix cross member and make a bridge to replace the member. Can send you pictures if you wish.
BTW the bearing is design to constant contact on the pressure plate fingers.
Graham has a good solution if you have the space, the simpler the better.
|We pulled the trans out without pulling the engine on a 1977 b. 215 buick and t5 trans. we had a lift and then just undid four bolts that hold th trans to bellhouseing. slid trans back, twisted it to one side and the it cleared the engin and we came forward with it. |
A lift helps and so does a strong friend to help man-handle the trans. Took about an hour.
|I'm with Steve on this one, I had to replace one of the internal O rings on my quartermaster HTOB. I had to undo the 4 trans to bellhousing bolts (helps if they are socket head cap screws), braced the back of the engine up, slid the tranny backwards over the fixed crossmember, tilted the front down, pulled it forward and it was out. Took about an hour with my brother helping, didn't have the car up in the air at all, just us strong-arming it up and down to get it out.|
|Jake & Steve,|
That is good to hear. I need to change my tranny and this is exactly how I was hoping to do it.
Anyone know how to determine if my HTOB is the improved version? So far no problems, but I have put some hard miles on it. :)
|Jake and Steve,|
Thanks for the reply. I'm a little more encourage that it will workout for me also. Well, you guys make it 3 (I believe that Glenn Towery also mentioned doing it)that pulled the tranny without removing the engine. Getting the top 2 transmission bolts out is my first concern. I remember (or I think I remember) looking at that situation when I installed the engine after a rebuild and concluding there wasn't enough room to get the bolts out. Soon I'll know.
Carl, I don't know all the upgrades to the Mcleod/Weber HTOB except these two. 1)banjo fittings for the hydraulic line were replace with 90 degree swivel fittings. 2) I believe the last upgrade was a different bearing. The new one is 3.2 inches diameter conpared to 2.7 for the older one.
I ordered the bearing for mine since that is the only problem I had. I'll see if it is as simple as Mcleod told me. I'll post the outcome next week.
Could you send the pictures of the cross member modification? Thanks
|Iíve had my motor and transmission in and out of the car countless times and never did I do both together. When removing the transmission I remove the bolted on cross support and leave the transmission tail shaft resting on the welded on brace. That much change in the angle allows access to the top two bolts using a universal with the ratchet and extensions. I do remove the shifter before unbolting the transmission and the transmission can then be shifted or rotated as needed to pull it far enough to clear the bell housing and lower it down and forward. You may want to bag the back to avoid a face full of gear oil.|
Again it all depends how far back you mounted your motor and what transmission you used, but odds are it will work and is far simpler than pulling the motor as well.
| Expanding on my previous post, a T-5 xsmn can be pulled by first removing the propshaft, the shifter, and speedo cable. The 4 mounting bolts are actually quite accessible and I do not remember having any difficulty with those. The fixed crossmember is also not a problem. The biggest issue, as I recall, was manhandling the xsmn weight while laying on my back.|
With the HTOB w/new swivel fittings, ensure that they fit inside the bellhousing opening (xsmn front face pilot hole) when reinstalling the xsmn/HTOB assembly. If the new is any wider than the the "old" style HTOB (which were a tight fit), then you might also have to remove the bellhousing.
|Guys, it seems to me that you can save yourself a lot fo frustration and expense if you can just fit a conventional external slave to a conversion.|
That is what I did on my MGA 3.4.
Is there a clearance problem with doing this in an MGB?
Bill asked: "Is there a clearance problem with doing this in an MGB?"
Well, yes... I originally fitted a conventional slave cylinder, but to make it fit I shortened the original Buick clutch release lever. I also had to make my own brackets, etc. Partly on account of having less lever arm length (i.e. "mechanical advantage") I suffered high pedal effort... so after several years I switched to a HTOB. In my case, pedal effort is certainly improved. To me, that was the whole reason to try a HTOB.
Still, I'm no fan of HTOBs, and I'm especially no big fan of the Tilton unit. If money were no object, I'd try a different brand next time. The Tilton unit proved fussy to adjust (because it's range of adjustment didn't allow as much extension as I'd like, and I'm right at its limit) and also fussy to bleed.
I'd strongly prefer the simplicity and servicability of a conventional slave cylinder.
|All done and it was a piece of cake. I pushed the car into the garage at 8:30 and was bleeding the new HTOB at 11:00. Once I saw that I would have access to the bolts I just went into cruise mode and chatted with a buddy while he work on another car. It turns out my concern for access to the upper transmission bolts was unwarranted. As Goerge mentioned, using swivel(s) and rachet extension(s) made getting to and removing(installing) quite easy. My Jeep was more difficult than this. Then, just pulled the tranny back over the x-member until the input shaft clear the bellhousing and lower it, front first, out of the car. |
My Weber HTOB was not the lastest version so I couldn't just replace the bearing, which would have been sooo much cheaper. The new unit has a larger bearing, 3.2inch diameter versus 2.7. The bearing part of my HTOB was completely shot and fell apart as we removed the transmission. There were only a few ball bearing left. I don't know what happened to the other ones.
I learned a few things about Weber/Mcleod HTOB. Components can be replaced. The bearing, the piston, o-rings, fittings. If I wasn't is a hurry I could have put a piston (~$50) and bearing ($71) into my unit.
Bill, I've not tried designing an external slave. Most posts I've read from those who have gone that route for buick or rover v8s were not encouraging.
This thread was discussed between 03/07/2006 and 10/07/2006
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