FRont caliper bolt HELP !
#1
FRont caliper bolt HELP !
I am replacing the front brake pads and rotors on my 1990 Jaguar XJS V12. I removed the caliper and put on the new rotor but now cannot get the lower caliper bolt back in. I have tried everything to line it up but nothing seems to work. The bolt goes through the first mount and the caliper but does not thread back in.
After about 10 tries and several hours I give up and really want to finish the job.
HELP !!
After about 10 tries and several hours I give up and really want to finish the job.
HELP !!
#2
Hi MIFoodie
Without knowing exactly the way you went about this, I'll have to Start from Scratch in the hope that you will get one of those 'Lightbulb Moments'
Where you go doh! I never thought of that, or else maybe you did!
First take off the Caliper and try the Bolt in the Threaded hole of the Hub
Screw it in and screw it out again, so that you know that the bolt will go in without any problem
Assuming it does, then put on the Caliper and very loosely put the bottom bolt in first, then just tighten it up a little bit (just nip it up)
Then using a feeler gauge, measure the thickness of the Shim or Shims, needed for the Top Bolt
Which could be One or Two Shims
If you did up the Top Bolt without inserting the Shims, that could be the reason why the Bottom Bolt won't Thread up and go in
Anyway back to the 'Plot'
Assuming you know how many of those Shims you are going to need, next take out the Bottom Bolt and replace that Bolt with a Screwdriver which should then be the only thing that is taking the weight of that Caliper
Then remove the Screwdriver that you put in the Bottom Bolt Hole of the Caliper and Replace it with a Bolt and then do it up a little bit
So it holds the Weight of the Caliper (it doesn't even need to be nipped up) just enough to pick up the Thread and a little bit more
Then put a Small bend in the Shim or Shims and Slot that Shim or Shims into the gap where the Shim goes at the Top Hole
Putting a little Bend in the Shim, will keep it in position and stop it falling out, where as soon as you see the Hole in the Shim, almost line up with the Hole in the Caliper
Put a Screwdriver through the Caliper, The Shim and the hole in the Hub and use the Screwdriver to 'Jiggle' the Shim into position
Then take out the Screwdriver and put in the Bolt, then 'Nip' The Top and Bottom Bolt up Tight and check all is OK
On the assumption that it is, then Torque up your Caliper Bolts as per the Manual and finally Wire them up
You can see how I did mine on Page: 85 of my 'Cherry Blossom' restoration thread
And here is a Link to that Page: https://www.jaguarforums.com/forum/x...122634/page85/
Without knowing exactly the way you went about this, I'll have to Start from Scratch in the hope that you will get one of those 'Lightbulb Moments'
Where you go doh! I never thought of that, or else maybe you did!
First take off the Caliper and try the Bolt in the Threaded hole of the Hub
Screw it in and screw it out again, so that you know that the bolt will go in without any problem
Assuming it does, then put on the Caliper and very loosely put the bottom bolt in first, then just tighten it up a little bit (just nip it up)
Then using a feeler gauge, measure the thickness of the Shim or Shims, needed for the Top Bolt
Which could be One or Two Shims
If you did up the Top Bolt without inserting the Shims, that could be the reason why the Bottom Bolt won't Thread up and go in
Anyway back to the 'Plot'
Assuming you know how many of those Shims you are going to need, next take out the Bottom Bolt and replace that Bolt with a Screwdriver which should then be the only thing that is taking the weight of that Caliper
Then remove the Screwdriver that you put in the Bottom Bolt Hole of the Caliper and Replace it with a Bolt and then do it up a little bit
So it holds the Weight of the Caliper (it doesn't even need to be nipped up) just enough to pick up the Thread and a little bit more
Then put a Small bend in the Shim or Shims and Slot that Shim or Shims into the gap where the Shim goes at the Top Hole
Putting a little Bend in the Shim, will keep it in position and stop it falling out, where as soon as you see the Hole in the Shim, almost line up with the Hole in the Caliper
Put a Screwdriver through the Caliper, The Shim and the hole in the Hub and use the Screwdriver to 'Jiggle' the Shim into position
Then take out the Screwdriver and put in the Bolt, then 'Nip' The Top and Bottom Bolt up Tight and check all is OK
On the assumption that it is, then Torque up your Caliper Bolts as per the Manual and finally Wire them up
You can see how I did mine on Page: 85 of my 'Cherry Blossom' restoration thread
And here is a Link to that Page: https://www.jaguarforums.com/forum/x...122634/page85/
The following users liked this post:
Greg in France (04-23-2018)
#3
Thanks for the details. The shims (2) were in the bottom bolt hole and I cannot get both shims in there and lined up with the bolt using the screwdriver as you suggest. If I try ti get in one shim I can get the bottom bolt to bottom out to the threads but it seems to not line up and grab the threads (even with 1 of the two shims.
I can keep trying as you suggest but hoped that there was another way.
I can keep trying as you suggest but hoped that there was another way.
#4
The BEST way to replace the rotors without needing to rebuild or repair the calipers is NOT REMOVE THEM!!!!!!!!!!!!!!!!!!!
I just remove the bolts from the back side with a FLEX SOCKET and maneuver the rotors past the spindle.
I only made the mistake of removing a caliper ONCE!!!!!!!!!
The shims and resetting the toe alignment convinced me to find a different way.
bob
I just remove the bolts from the back side with a FLEX SOCKET and maneuver the rotors past the spindle.
I only made the mistake of removing a caliper ONCE!!!!!!!!!
The shims and resetting the toe alignment convinced me to find a different way.
bob
The following 2 users liked this post by motorcarman:
Doug (04-23-2018),
Robert Laughton (04-23-2018)
#5
Thanks for the details. The shims (2) were in the bottom bolt hole and I cannot get both shims in there and lined up with the bolt using the screwdriver as you suggest. If I try ti get in one shim I can get the bottom bolt to bottom out to the threads but it seems to not line up and grab the threads (even with 1 of the two shims.
I can keep trying as you suggest but hoped that there was another way.
I can keep trying as you suggest but hoped that there was another way.
Steering arm; shims as needed; calliper; and the bolt threads into the upright.
The lower bolt cannot bottom out into the upright if the correct bolt and assembly order is in place.
I would ensure the calliper has no pads in it yet, then (very important) loosen the steering arm top bolt a but (the one above the stub axle fixing)and then get the lower bolt started with everything loose. Once it is threaded into the upright a couple of turns, start the top calliper bolt. Once that is done, tighten the top steering arm bolt and the top calliper bolt. Then proceed as OB suggested.
#6
Hi MIFoodie
Having replaced the Calipers on Three of my XJS's
I have never considered this as being a difficult job, although it could take the best part of a day, what with all the Torquing and Wiring up of the Bolts
The only other reason why you might be having a problem (that I can think of right now)
Is that you haven't dropped the Track Rod Ball Joint on the Steering Arm before you started
In my own experience (though maybe not of others) This can make Changing the Calipers a lot easier, as you can then pull the Hub round to get a better look at what you are doing
Plus it also gives you a lot more room to work, as does doing this job outside in the open
Having replaced the Calipers on Three of my XJS's
I have never considered this as being a difficult job, although it could take the best part of a day, what with all the Torquing and Wiring up of the Bolts
The only other reason why you might be having a problem (that I can think of right now)
Is that you haven't dropped the Track Rod Ball Joint on the Steering Arm before you started
In my own experience (though maybe not of others) This can make Changing the Calipers a lot easier, as you can then pull the Hub round to get a better look at what you are doing
Plus it also gives you a lot more room to work, as does doing this job outside in the open
The following users liked this post:
Hedman (04-18-2020)
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