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MG MGB GT V8 Factory Originals Technical - HTOB

For those still contemplating the solution of their clutch installation, Howe Racing Products has recently released a HTOB for street car usage that will supposedly bolt to GM transmissions (& all t-5's I presume). It ships with all mounting hardware and a shim assortment to allow adjustment to most situations. I ordered one from Speedway Motors ($149) and will report on it's success or failure soon.

does this HTOB also work for the 5-speed Rover box?
werner van clapdurp

Werner, I don't know if it will or not. I received the bearing assembly from Speedway and tried it on my T-5 and it fits perfectly. When it's installed, a special bolt with an smooth extension replaces one of the original 4 bolts that secures the front bearing retainer to the case. That extended bolt then becomes a guide for the HTOB to keep it from turning in use. The ID of the HTOB is a slip fit over the retainer (maybe .010" clearance) so that it moves easily but there isn't excessive clearance. The id of the HTOB is 1.375 (appx). The instructions say only that the application is for "Chevy Transmissions". I've got a couple of photos if you'd like me to e-mail them.


I called Howe racing and spoke with them about the bearing. The only thing they said was that you may have to shave the collar so the bearing would not be always engaged. Does it look like that may be a problem? I was not sure if he meant shortening the collar or shaving some off of the base.
Let me know how it works because it is a lot cheaper than Mcleod.
When I spoke to Mcleod they mentioined that the clutch had to be depressed about every two weeks when the car is not being driven to keep the seal lubricated. I wonder if the same is true with Howe's bearing?

I won't know for sure until I test assemble the engine to trans, which may be next weekend. Shaving material off either part looks relatively simple. I don't know about keeping the seal lubed, but pickups have been using HTOB's for years and they don't seem to have a problem. In reading the literatue for this particular HTOB, it was designed for stock type clutchs which means it has adequate travel (.700") designed in, so over-extending the cylinder should not be an issue either, so long as the bearing to pressure plate clearance is correctly set. I'll post an update as soon as I test fit the trans.


I'm very interested in what you find and any lessons you learn while installing this. I got a Howe HTOB the other day and it does seem to fit the T-5 bearing retainer very well but I'm about a month away from being able to mate the trans and engine for a test fit. Keep us posted on your progress!
Scott Costanzo

heres a question: will a HTOB work with both a diaphram style pressure plate and the 3 finger borg and beck style? if not, which one wont work?

Here's a better question than Jake's.
What is an HTOB anyway and what does it do?

HTOB = Hydraulic Throw Out Bearing. its used instead of a clutch slave cylinder, pushrod, pivot ball and arm, and standard release bearing. it operates on hydraulic pressure from the clutch master cylinder, filling with fluid when the pedal is depressed, and expanding enough to disengage the clutch disk. it cuts down on alot of "suspect" parts ie. alot of variables in the clutch that could fail.

The HTOB takes the place of the clutch hydraulic slave cylinder. The HTOB is mounted to the front of the tranny, and fits around the tranny input shaft. When the clutch is depressed, the lines carry fluid pressure from the clutch master cylinder to the HTOB, causing it's internal cylinder to expand forward, and pushing the throwout bearing part of it to apply pressure to the clutch pressure plate fingers, thus releasing the clutch. Hope that clears things up.

Jake, to the best of my knowledge, the HTOB will work with any type of pressure plate just as any throwout bearing would.

Joe Ullman

I test fit my transmission and clutch setup to the engine and these are the results: The Howe HTOB fit without modification and my particular flywheel/clutch/bellhousing arrangement required me to add .750" of shim between the HTOB (included with the HTOB) and the T-5 trans bearing retainer (nose piece). Sometimes, things work right the first time. By the way, I overhauled my T-5 Trans with a Hanlon Motorsports overhaul kit and video. See their website. Piece of cake. If you can build one of these cars, you can overhaul a T-5.


Gordon are you use a Ford or GM T5?? I unfotunately think they are a little different in input shaft area. I liked thier push and pull slave cylinders.. caught my eye bigtime.. Problem is that they would require a different master cylinder.

Larry Embrey


My T-5 is a GM Non-World Class from a 1983 Camaro V6. Not my first choice, but definitly acceptable. The Trans was sold to me as being in servicable condition, but I wanted to freshen it to be sure. Turns out several of the synchro keys had broken and were lying on the bottom of the trans. One thing I haven't been able to check yet is the effectivness of the existing MG master cyl. with the Howe HTOB. I'd read on another board that it had been used with success, so I'm not overly concerned.


Does anyone know what the volume of fluid displaced during pedal depression of the std. MGB clutch master cylinder?

Wayne Pearson

This thread was discussed between 02/04/2002 and 16/04/2002

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