Getting a Hydramax hydraulic throwout bearing to fit my A833 OD transmission

[Dakota]

I'm documenting the approach I used to get a Hydramax hydraulic release (throw-out) bearing from American Powertrain to work with my A833 OD transmission and McCleod 3 finger clutch in hopes that it may help someone else.

The Hydramax kit comes with a series of shims to move the throw-out bearing face to within 0.150-0.200" of the clutch fingers, with this air gap allowing for some "free play" in the clutch pedal initially and as the clutch surface wears.   When I did all the measurements spelled out in the instructions, it turned out with my setup there was a need to create space rather than fill it.  I can't say that this problem will exist on all A-833's as a quick check of pictures on the internet showed several different lengths of the "collar" (see picture below - not mine but included for illustration) that's part of the input shaft bearing retainer on the transmission. 

The blue part in the 2nd picture is called the "floating stud carrier" which rests against the collar.  To get the proper air gap, I needed to remove a 1/16" wide ring from the inner diameter of the floating stud carrier where it meets the collar to a depth of about 1/4".   One simple way to do this is to use a small router with a carbide bit equipped with a slightly smaller guide bearing.  The carbide bit can easily cut aluminum.   I used a bit with a 1/2" diameter cutting head and a 3/8" diameter guide bearing.

Truth be told, I made a mistake in my measurements the first time I used the router and didn't cut deep enough.   My reward for not "measuring twice, cutting once" was to drop the transmission and do it all over again as I didn't have hardly any free play on the clutch pedal.   All better now.

Anyways, hopefully this will help another member here if they end up with a similar situation.

[xx88man]

I'm learning.... what is the advantage to having that throw-out bearing?

[gzig5]

Thanks for posting your experience.  I'm leaning toward a hydraulic setup on my conversion to avoid messing with the z-bar and linkage, which I don't have.  Either the American Powertrain like yours, or possibly a cobbled master/slave using the regular throw-out fork.
Did you get a complete kit with master cylinder or piece it together yourself? 
Are you using the big spring on the clutch pedal or does that get eliminated with the hydraulic setup?

[Dakota]

I'm learning.... what is the advantage to having that throw-out bearing?

A car I owned previously (not a Mopar) had a hydraulic throw-out bearing that made for smoother, easier clutch work. compared to my limited experience with mechanical linkage.   I'm a fairly large person so a heavy clutch pedal wouldn't really bother me, but I wanted to make sure it was possible for my wife to drive the car too.

With a hydraulic set up, there are fewer moving parts which generally means there are less things to wear out or adjust.   It wasn't a factor in my decision, but I believe the hydraulic route also frees up space for headers.

As you'll see in my next reply, getting things set up for the hydraulic bearing on my car involved quite of bit of fiddly work that wasn't obvious from watching YouTube videos or reading the instructions.  Having already spent the money on the kit, I stubbornly stayed after it until everything was sorted out.

The shop manager where I take my Challenger is not a fan of hydraulic bearings as he believes the weight of the cars puts too much strain on them.   So far I'm ignoring his encouragement to go back to the stock set up.

A hydraulic bearing can make quite a mess if it leaks, with over-extending beyond the intended travel range of the bearing being one of the main failure routes from what I've read.

I know there are people on the forum with lots more experience than me with both the stock set up as well as the hydraulic route, so hopefully they will chime in here too.

[JonH]

Thanks for posting your experience.  I'm leaning toward a hydraulic setup on my conversion to avoid messing with the z-bar and linkage, which I don't have.  Either the American Powertrain like yours, or possibly a cobbled master/slave using the regular throw-out fork.
Did you get a complete kit with master cylinder or piece it together yourself? 
Are you using the big spring on the clutch pedal or does that get eliminated with the hydraulic setup?

This is what I did for a couple hundred bucks. Did end up moving the slave connection on the fork to stock location for better leverage. Yes I am using the over center spring. 3 finger ram clutch...

[Dakota]

Thanks for posting your experience.  I'm leaning toward a hydraulic setup on my conversion to avoid messing with the z-bar and linkage, which I don't have.  Either the American Powertrain like yours, or possibly a cobbled master/slave using the regular throw-out fork.
Did you get a complete kit with master cylinder or piece it together yourself? 
Are you using the big spring on the clutch pedal or does that get eliminated with the hydraulic setup?

I bought a complete kit from American Powertrain - master cylinder with adjustable mounting bracket, throw-out bearing (pre-bled), shims, fluid reservoir and hoses.

The biggest unexpected challenge I had in the installation was where to attach the pushrod on the clutch pedal for the hydraulic throwout bearing master cylinder.    It's VERY important to have reach the 6:1 ratio for pedal movement:pushrod movement that's described in the instructions because otherwise you have to be pretty beastly with leg strength which defeats one of the main reasons to get the hydraulic bearing in the first place.   You can read more on that discussion thread here:

https://forum.e-bodies.org/engine-transmission-and-rear-end/4/location-on-clutch-pedal-for-hydraulic-throw-out-pushrod-connection/18048/msg235618#msg235618

Things definitely got a little snug around the firewall between the bearing's master cylinder location and the brake booster/master cylinder.  It's doable, but tight.   If you go to the bottom of the page in the link that follows, you can see one option for where to mount the master cylinder.   There are certainly other variations on this that will work.

https://forum.e-bodies.org/your-restoration-project-roseville-moparts/10/70-challenger-going-plum-crazy/3743/90


I elected to add a bracket from SST to tie the the bearing master cylinder to the frame rail to reduce the stress on the firewall.


Another space challenge was the location of the reservoir for the master cylinder.   You can read more about this topic here:

https://forum.e-bodies.org/engine-transmission-and-rear-end/4/placement-of-reservoir-for-hydraulic-throw-out-bearing/12877/msg207886#msg207886

The only other big thing I remember biting me in the butt on the installation was that I couldn't get the bearing to move initially.   After following the instructions for pump bleeding (very much like doing brakes) with no success, I had to use their other recommended path of opening the bleeder cap to let the system gravity drain for a couple of hours while keeping an eye on the reservoir level.    I think I had an air pocket trapped in the master cylinder because of the steep angle used.   The gravity bleeding finally did the trick.

At this point, I still have the stock "over center" spring for the clutch pedal installed.   I'm going to run a test in the next couple of days without it and see how much of a difference it makes.   I'll add a note to this thread once it's done.

Yes, it was more effort that I originally expected to get this in, but that's no different that everything else on these cars, especially when retrofitting a component that wasn't part of the original design.   I will also tell you that while going for a drive yesterday, I forgot all about the scrapes and skinned knuckles that went with the restoration.

Hope this helps.   

[AndR]

Good day to all, I am new to this forum, JonH I really like your setup for the hydraulic clutch but I'm wondering where you got the angle mount for you master cylinder? It looks awesome

[JonH]

Good day to all, I am new to this forum, JonH I really like your setup for the hydraulic clutch but I'm wondering where you got the angle mount for you master cylinder? It looks awesome

I made it.

[Dakota]

Are you using the big spring on the clutch pedal or does that get eliminated with the hydraulic setup?

I know this is an older post but I wanted to circle back on this question.   The latest revision of American Powertrain's installation instructions for the Hydramax throwout bearing now specifically states to remove the overcenter spring.   I removed mine before putting my car back on the road this season.   The clutch and pedal work fine without it other than the pedal is a little harder to push.

Also, in the picture below, note the location (and candid comment about how the stock location "sucks") in the instructions on where to locate the pushrod connection on the clutch pedal to the throwout bearing's master cylinder for an E-Body.   Naturally, I came across these instructions after repositioning the "arm" on the clutch pedal a second time to get the 6:1 ratio for pedal:pushrod movement using the stock pin location.