A tip for XJ owners and others

Last week I had a thumping noise coming from under my 88 XJ and thought the
weird (and expensive ... if you can find one) transmission mount for the
BA10/5 transmission had finally bit the dust.

Rather, I found the metric crossmember-to-unibody bolts for the driver's
side were stripped! Some idiot that shouldn't be on the same planet as tools
had overtightened them at some point (impact wrench????) before I bought the
vehicle and a chuckhole caused them to loosen a bit, making the noise
everytime I applied my brakes.

A few minutes with a jack, drill bit, 13/32", drill, 7/16-20 tap 7/16-20 X 1
1/2" machine screw (Grade 5), 7/16" lock and flat washers and I had it
fixed. I was able to give the new bolts full torque (55 ft/lb dry, 40 ft/lb
oiled) and now that side is stronger than the passenger side.

Judging from the ease of tapping, the metal used for the hidden nuts is
fairly soft, so anything over grade 5 is a waste of money.

The other side will have to wait till spring.
--
C.L. "Budd" Cochran
Pray for the Obama administration: Psalm 109:8
http://truefree1776.blogdrive.com/

Budd Cochran wrote:

> Last week I had a thumping noise coming from under my 88 XJ and thought
> the weird (and expensive ... if you can find one) transmission mount for
> the BA10/5 transmission had finally bit the dust.
>
> Rather, I found the metric crossmember-to-unibody bolts for the driver's
> side were stripped! Some idiot that shouldn't be on the same planet as
> tools had overtightened them at some point (impact wrench????) before I
> bought the vehicle and a chuckhole caused them to loosen a bit, making the
> noise everytime I applied my brakes.
>
> A few minutes with a jack, drill bit, 13/32", drill, 7/16-20 tap 7/16-20 X
> 1 1/2" machine screw (Grade 5), 7/16" lock and flat washers and I had it
> fixed. I was able to give the new bolts full torque (55 ft/lb dry, 40
> ft/lb oiled) and now that side is stronger than the passenger side.
>
> Judging from the ease of tapping, the metal used for the hidden nuts is
> fairly soft, so anything over grade 5 is a waste of money.
>
> The other side will have to wait till spring.

Question: how the heck did you keep the captive nuts from spinning as you
tapped them? I finally had to tack weld the crimp on mine to get them
tapped but that a tad drastic if there is another way....

--
Will Honea

I really don't know why they didn't spin, but I used WD-40 to lube the tap
and flush the chips. Normally I use either congealed bacon drippings or
sulphated cutting oil.

I only cut a quarter turn at a time, backed out enough to snap the chips
loose and then went again ... very slow and careful. No hard twisting, nice
and easy.

Every full turn or turn and a half, I backed out enough to break chips then
I shot the WD in to flush and re-lube things.

On my XJ there's no, zero, nada, access to the captive nuts (frame welded to
body) so I couldn't have even welded them if they had spun and that's why I
went so slow. Plus I didn't want to drop the crossmember if I didn't have
to, so I drilled and tapped right up through it.

Looking back, I understated the time required ... I was laying on a cold
driveway for an hour at least.

My apologies on that.

And you can go 1/32" bigger on the drill if you have to and not lose much
thread strength. That will make tapping easier also.

--
C.L. "Budd" Cochran
Pray for the Obama administration: Psalm 109:8
http://truefree1776.blogdrive.com/



"Will Honea" > wrote in message
...
> Budd Cochran wrote:
>
>> Last week I had a thumping noise coming from under my 88 XJ and thought
>> the weird (and expensive ... if you can find one) transmission mount for
>> the BA10/5 transmission had finally bit the dust.
>>
>> Rather, I found the metric crossmember-to-unibody bolts for the driver's
>> side were stripped! Some idiot that shouldn't be on the same planet as
>> tools had overtightened them at some point (impact wrench????) before I
>> bought the vehicle and a chuckhole caused them to loosen a bit, making
>> the
>> noise everytime I applied my brakes.
>>
>> A few minutes with a jack, drill bit, 13/32", drill, 7/16-20 tap 7/16-20
>> X
>> 1 1/2" machine screw (Grade 5), 7/16" lock and flat washers and I had it
>> fixed. I was able to give the new bolts full torque (55 ft/lb dry, 40
>> ft/lb oiled) and now that side is stronger than the passenger side.
>>
>> Judging from the ease of tapping, the metal used for the hidden nuts is
>> fairly soft, so anything over grade 5 is a waste of money.
>>
>> The other side will have to wait till spring.
>
> Question: how the heck did you keep the captive nuts from spinning as you
> tapped them? I finally had to tack weld the crimp on mine to get them
> tapped but that a tad drastic if there is another way....
>
> --
> Will Honea
>

Budd Cochran wrote:

> I really don't know why they didn't spin, but I used WD-40 to lube the tap
> and flush the chips. Normally I use either congealed bacon drippings or
> sulphated cutting oil.
>
> I only cut a quarter turn at a time, backed out enough to snap the chips
> loose and then went again ... very slow and careful. No hard twisting,
> nice and easy.
>
> Every full turn or turn and a half, I backed out enough to break chips
> then I shot the WD in to flush and re-lube things.
>
> On my XJ there's no, zero, nada, access to the captive nuts (frame welded
> to body) so I couldn't have even welded them if they had spun and that's
> why I went so slow. Plus I didn't want to drop the crossmember if I didn't
> have to, so I drilled and tapped right up through it.
>
> Looking back, I understated the time required ... I was laying on a cold
> driveway for an hour at least.
>
> My apologies on that.
>
> And you can go 1/32" bigger on the drill if you have to and not lose much
> thread strength. That will make tapping easier also.

Translation: I got lucky ;-)

The captive nuts I'm most familiar with are the ones with a small section
that fits thru the frame with the end of the thru-section rolled over to
crimp the whole mess. I usually tack weld the exposed rolled part but the
one I remember best was the one that simply pushed back into the frame - old
Jeeps and rust have this affinity... Anyway, the was a larger hole fairly
near to the spot where the thing popped out so I was able to fish a nut over
the hole and get a long bolt started into it. That held it long enough to
weld the nut to the side of the hole but it was a fight.

Another trick with a turning nut I was shown was to thread a stud into it
then use a thin halfnut to cinch it down while I worked. Still a PITA on a
22 year old vehicle!

--
Will Honea