- Joined
- Sep 26, 2003
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- 117
- Messages
- 11,207
- Location
- Lancaster, Ohio, USA
- Website
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Fascinating post mortem on what should have been a straightforward clutch adjustment or R&R.
Vehicle: stock 75 FJ40
Customer complaint: Noisy clutch pedal.
Noted on test drive: clutch pedal out of adjustment.
Initial inspection reveals underside of truck, interior floor and engine bay coated w/ mud. Not good for clutch parts. Pulling clutch inspection cover off BH reveals BH full of mud.
Problem #1. The front BH cover is MIA, allowing mud to be scooped into BH.
#2. Mud has contaminated the release bearing, causing it to dry out and seize.
#3. bolts holding the tranny to BH have been replaced w/ smaller diameter UNC nuts & bolts.
#4. there are only 3 of the 4 undersize bolts holding tranny to BH. Parting line is visible, indicating relative motion between BH and tranny, explaining odd feeling of clutch pedal. Hole #4 has a coarse thread 12mm bolt loosely stuck in it.
So it is time to R&R tranny, replace the missing bolts & replace clutch.
Drop tranny, find that the reason the BH bolts were replaced is because the threaded holes have been destroyed.
#5. All 4 threaded holes have been completely stripped out and destroyed.
#6. shifter boot on top of tranny is MIA, allowing mud & water into top of trans (the thick mud on top of tranny and on floor inside truck indicate that the tranny has been underwater repeatedly).
#7. speedo cable is wrapped around exhaust pipe, vinyl sheath burned off.
OK, fine, we will replace the BH w/ one that has not been 'modified'. Put a jack under OP, pull off clutch. Hey, there are only 4 bolts (of 6) holding BH to block.
That explains the mystery coarse thread bolt in the transmission ear.
#8. Missing BH bolts into back of block. Threads are OK.
Remove motor mounts to pull BH, find that one of the bolts is missing. no surprise at this point. Drop BH out, motor mount bolt is not missing, but broke off in BH.
#9. one lower (stressed) bolt broken off in side of BH
#10. motor mount through bolt is badly bent?
#11. both rubber boots missing from sides of BH, allowing more mudwater entry.
Looking at block face of BH, there is something funny w/ cam plug. Inspection reveals cam plug is loose in block, spinning freely and driven by camshaft. Plug has been holesawing at front of BH. also explains oil leak at rear of engine, despite new, dry rear main seal.
#12. Engine rebuilt w/ wrong cam plug.
New correct toyota plug is installed. Fortunately, bore in block is not damaged, plug is still a good tight fit.
Inspecting clutch release lever and TO bearing, we find that the TO bearing hairpin clips have been replaced by roofing nails. This required drilling the hairpin holes quite a bit bigger. The nails have caused excessive wear on the TO ears.
#13. Wrong clutch clips.
#14. damaged/modified release fork and TO hub.
I am not taking anything else apart on this time bomb.
Time to go back together:
New clips and hub are sourced from Toyota. Good used release fork is installed.
New rubber boots installed on shifter & BH.
Good used BH is installed, replacing damaged fasteners as necessary.
New OEM clutch is installed on resurfaced flywheel.
Tranny is stabbed in and bolted up w/ new Toyota bolts.
Release cylinder is properly adjusted.
Missing front BH dust shield is installed.
BH pan is installed w/ all fasteners.
PTO driveshaft is installed w/ new correct Toyota bolts.
New speedo cable installed, routed correctly around PTO and exhaust.
Pics to come.
DSY6M
Vehicle: stock 75 FJ40
Customer complaint: Noisy clutch pedal.
Noted on test drive: clutch pedal out of adjustment.
Initial inspection reveals underside of truck, interior floor and engine bay coated w/ mud. Not good for clutch parts. Pulling clutch inspection cover off BH reveals BH full of mud.
Problem #1. The front BH cover is MIA, allowing mud to be scooped into BH.
#2. Mud has contaminated the release bearing, causing it to dry out and seize.
#3. bolts holding the tranny to BH have been replaced w/ smaller diameter UNC nuts & bolts.
#4. there are only 3 of the 4 undersize bolts holding tranny to BH. Parting line is visible, indicating relative motion between BH and tranny, explaining odd feeling of clutch pedal. Hole #4 has a coarse thread 12mm bolt loosely stuck in it.
So it is time to R&R tranny, replace the missing bolts & replace clutch.
Drop tranny, find that the reason the BH bolts were replaced is because the threaded holes have been destroyed.
#5. All 4 threaded holes have been completely stripped out and destroyed.
#6. shifter boot on top of tranny is MIA, allowing mud & water into top of trans (the thick mud on top of tranny and on floor inside truck indicate that the tranny has been underwater repeatedly).
#7. speedo cable is wrapped around exhaust pipe, vinyl sheath burned off.
OK, fine, we will replace the BH w/ one that has not been 'modified'. Put a jack under OP, pull off clutch. Hey, there are only 4 bolts (of 6) holding BH to block.
That explains the mystery coarse thread bolt in the transmission ear.
#8. Missing BH bolts into back of block. Threads are OK.
Remove motor mounts to pull BH, find that one of the bolts is missing. no surprise at this point. Drop BH out, motor mount bolt is not missing, but broke off in BH.
#9. one lower (stressed) bolt broken off in side of BH
#10. motor mount through bolt is badly bent?
#11. both rubber boots missing from sides of BH, allowing more mudwater entry.
Looking at block face of BH, there is something funny w/ cam plug. Inspection reveals cam plug is loose in block, spinning freely and driven by camshaft. Plug has been holesawing at front of BH. also explains oil leak at rear of engine, despite new, dry rear main seal.
#12. Engine rebuilt w/ wrong cam plug.
New correct toyota plug is installed. Fortunately, bore in block is not damaged, plug is still a good tight fit.
Inspecting clutch release lever and TO bearing, we find that the TO bearing hairpin clips have been replaced by roofing nails. This required drilling the hairpin holes quite a bit bigger. The nails have caused excessive wear on the TO ears.
#13. Wrong clutch clips.
#14. damaged/modified release fork and TO hub.
I am not taking anything else apart on this time bomb.
Time to go back together:
New clips and hub are sourced from Toyota. Good used release fork is installed.
New rubber boots installed on shifter & BH.
Good used BH is installed, replacing damaged fasteners as necessary.
New OEM clutch is installed on resurfaced flywheel.
Tranny is stabbed in and bolted up w/ new Toyota bolts.
Release cylinder is properly adjusted.
Missing front BH dust shield is installed.
BH pan is installed w/ all fasteners.
PTO driveshaft is installed w/ new correct Toyota bolts.
New speedo cable installed, routed correctly around PTO and exhaust.
Pics to come.
DSY6M
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