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Throttle shaft bearing/bush on bulkhead

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warwick-steve

warwick-steve

Jedi Hopeful
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Hi
I have a tricarb BT7 which has a throttle shaft rotating in a "countershaft support" and supported in a bearing/bush on the bulkhead.
Does this end bearing/bush need lubrication?
Can the bush be easily replaced?
Thanks in advance for our help
Steve
 
The bulkhead bearing for the throttle shaft is a rubber grommet with a bronze/brass machined bushing bonded to the rubber in the centre . It shouldnt need lubrication but some dry lubricant may help . Its easily replaced , make sure the metal frame that supports it is not bent as that will mean the centre bushing isnt lined up correctly with the shaft and cause binding .
 
The difficulty in replacing the bulkhead bearing is that it's usually the rubber grommet that perishes. It is too easy to end up with the grommet being pushed into the horizontal heater duct, which is difficult to access without removing the heater.
 
John Turney said:
The difficulty in replacing the bulkhead bearing is that it's usually the rubber grommet that perishes. It is too easy to end up with the grommet being pushed into the horizontal heater duct, which is difficult to access without removing the heater.
Click to expand...

The BJ7 & BJ8 solved this by mounting a bracket on the firewall, into which the same grommet/bearing goes. It would probably be simple to install this bracket, along with a plug for the hole in the firewall.
 
Hi
I just looked at the assembly. There is a bracket mounted on the firewall by two screws into which the grommet /bearing is fitted. (There is a rubber plug in the firewall about 4cm directly below the bracket.)
I presume to fit a new grommet/bearing it is necessary to undo the linkages and slide the shaft forward to allow the grommet/bearing to be slid onto the end and then located into the bracket.
Sorry but I don't understand how the grommet could be pushed into the horizontal heater duct, maybe I have the bracket that steveg mentions.
thanks again
Steve
 
Mines a BJ8 but its probably similar .
Take off the carb linkage and push out the bushing .
 

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warwick-steve said:
Hi
I just looked at the assembly. There is a bracket mounted on the firewall by two screws into which the grommet /bearing is fitted. (There is a rubber plug in the firewall about 4cm directly below the bracket.)
I presume to fit a new grommet/bearing it is necessary to undo the linkages and slide the shaft forward to allow the grommet/bearing to be slid onto the end and then located into the bracket.
Sorry but I don't understand how the grommet could be pushed into the horizontal heater duct, maybe I have the bracket that steveg mentions.
thanks again
Steve
Click to expand...
Sounds like you have the bracket that Steve mentions. I have a BN4 where the grommet is in the firewall, and no bracket.
 
warwick-steve said:
Hi
I just looked at the assembly. There is a bracket mounted on the firewall by two screws into which the grommet /bearing is fitted. (There is a rubber plug in the firewall about 4cm directly below the bracket.)
I presume to fit a new grommet/bearing it is necessary to undo the linkages and slide the shaft forward to allow the grommet/bearing to be slid onto the end and then located into the bracket.
Sorry but I don't understand how the grommet could be pushed into the horizontal heater duct, maybe I have the bracket that steveg mentions.
thanks again
Steve
Click to expand...

Steve - if you have the bracket per picture below, you should be able to remove the screws at 9 and 3 o'clock and swivel your rear throttle rod enough to slide the bracket with bearing off toward the firewall. There is no clip holding it on.

When you have the bracket on the bench, insert the bearing grommet there.

I used to have the bearing in the firewall per John T above (plug to LR of bracket), but added the BJ8 bracket when I added my HD8 carbs.

screenshot.1564.jpg
 
Hi Steve
There is very little access close to the bracket on the tricarb set up. From what I can see, there is just about enough room to replace the grommet as follows.
- unscrew bracket/grommet and slide forward on shaft as far as possible
- push out grommet to rear and slide off shaft.
- push in new grommet from rear side of bracket
- slide bracket back into position and screw up.

To have to dismantle the shaft and linkages would be a real pain so would hope the above procedure works out.
From closer inspection the rubber grommet looks in reasonable condition so will delay changing until absolutely necessary.
Thanks to all for your advice
Steve
 
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