Mazda BT 50 & Pickup Trucks While Mazda may not be known for their trucks, they have always produced quality reliable trucks for both hauling cargo, or simply crusing. BT 50

Clutch problems

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  #21  
Old 11-23-2023, 09:13 AM
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Originally Posted by 90-B2200
Somewhere along the line the return spring on the clutch pedal fell off. I suppose we should source another one.
Yes - that's important !!! This "might be" Mazda part H00141081B. https://www.jimellismazdaparts.com/s...modelYear=1990 Or, if you're lucky, you could find one close in the drawers at Ace Hardware or similar.

Originally Posted by 90-B2200
There are two electric switches associated with the clutch pedal assembly. I know the lower one (engaged when pedal is pressed fully to floor) is to prevent the engine from cranking unless the pedal is down. What it the upper one for? The one that engages when the clutch is all the way up.
Yes, that one switch is the interlock safety switch for the starter (I recently had mine out to disassemble and clean that out due to intermittent high resistance, making it tough to crank sometimes).

The other switch would be to disengage cruise control.
 
  #22  
Old 11-23-2023, 09:26 AM
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Originally Posted by Cusser
The other switch would be to disengage cruise control.
Hmmm, I’m pretty sure this truck was not equipped with cruise control. Would the cruise control cut off switch still be there even if the other components were never installed?

 
  #23  
Old 11-23-2023, 11:02 AM
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Originally Posted by 90-B2200
Hmmm, I’m pretty sure this truck was not equipped with cruise control. Would the cruise control cut off switch still be there even if the other components were never installed?
My 1988 SE-5 did not come with cruise control, and only has one clutch pedal switch. So that's my only guess, and don't know if by 1990 they came with such switch already there. Maybe someone else knows.

Trucks equipped with factory cruise control also had a second switch for that on the brake pedal - does yours have that???
 
  #24  
Old 11-23-2023, 11:07 AM
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The truck is not here at my address at the moment. I’m not sure off hand what the switch arrangement is on the brake pedal.

On the GM vehicles I have, the cruise control cut off is done by the actual brake light switch so on those it’s one switch performing two functions.
 
  #25  
Old 11-23-2023, 01:48 PM
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Originally Posted by 90-B2200
On the GM vehicles I have, the cruise control cut off is done by the actual brake light switch so on those it’s one switch performing two functions.
Same as I have wired up on both my 1998 and 2004 Frontiers, which have aftermarket Rostra universal cruise control units actuated by the brake light switch.
 
  #26  
Old 11-26-2023, 03:23 PM
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Update: We installed a new master and slave today. Bench bled the master before installing and followed up with pressure tank bleeding after both parts were installed. I'm beyond sure we got all air out. The clutch release fork moved a tad more after all this but its still wouldn't allow us to put it in gear with the engine running. I then adjusted the pushrod to pretty much the maximum length and finally, barely, we could put it in gear.

Prior to today we were only getting maybe 1/2" push of the slave on the fork. After the work today we are getting almost a full 1" push back on the fork. This doubled movement just barely allows us to put it in gear with the engine running and only if you push the pedal completely to the floor. When driving the clutch begins engaging as soon as you begin to let the pedal up off the floor. This is with maximum pushrod length which should make the engagement point when the pedal is much farther up off the floor.

When I asked my stepson exactly what was happening right before he had the problem and got stranded he said this. He said the pedal got really hard to push so he had to forcefully push to get it to go down. Then when he let up, that is when the pedal went mushy and stayed closer to the floor even when fully released,

His description of these events makes me think one of the release fingers broke on the pressure plate and jammed it up making it hard for him to push the pedal down. Subsequently the piece maybe dislodged allowing free pedal movement but with a broken pressure plate, now thats why we continue to have the problem.

By ruling out hydraulic problems and regaining nearly a full 1" fork movement, I'm heavily leaning to broken pressure plate.

We gained just enough function for me to drive it from his house where it was parked in the grass on a hill, to my house where it now sits on a level concrete slab in my enclosed and well equipped garage.

I'm pretty sure we're pulling this trans. Meanwhile, are there and openings that allow inspection to even minimal degree before complete removal?

Thanks again gents.
 
  #27  
Old 11-27-2023, 09:06 AM
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I think this is what I'd do at this point if my B2200 had same issue.
#1. Re-check the gear oil level in the transmission, at fill plug on the side of the transmission. If significantly low, I'd add GL-4 gear oil to top off. If at fill plug or close, then I'd consider draining the gear oil and adding fresh GL-4 (because that would be reasonable when I went to Step #2).

#2. I'd pull the transmission and replace the clutch components, including pilot bearing, throwout bearing, pressure plate, and disc. And I'd get the flywheel resurfaced, and maybe replace the rear oil seal while that was off. And do this especially if you don't know the mileage on your clutch. I see complete Exedy and Luk clutch kits on RockAuto for under $100; I have Luk on my '88 B2200 since about 2005, and have Exedy in my Frontier. Rock Auto discount codes to try: 223013748200701260, expires on December 8, 2023 250265786205571282, expires Dec 22, 2023
https://www.rockauto.com/en/catalog/...lutch+kit,1993

And if I didn't change out gear oil in Step #1, I would drain and re-fill. Manual transmissions historically are very sturdy.
Clutch replacement


 
  #28  
Old 11-27-2023, 09:13 AM
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On the fluid, it had a full drain and refill with Mobile 1 full synthetic transmission fluid about 50k miles ago. There are no transmission fluid leaks.

We’ve got our eyes on the LUK clutch kit. Planning on a LUK flywheel too and maybe a fresh rear main seal.
 
  #29  
Old 11-29-2023, 06:01 AM
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Originally Posted by 90-B2200
On the fluid, it had a full drain and refill with Mobile 1 full synthetic transmission fluid about 50k miles ago.
Correction. The fluid used was Mobile 1 full synthetic 75w-90 gear oil
 
  #30  
Old 11-29-2023, 06:04 AM
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Anybody know what this switch is for? It's on the right rear tail of the transmission. It's not the backup light switch because I'm pretty sure that is the one on the other side.


 


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