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S Belt rubbing

S

Samuryan

NAXJA Forum User
Location
Makawao, HI
OK i'm going to ask a question i probably already know the answer to but any info is appreciated. Just changed the rad. on my 88 4.0 xj noticed that the ps pump tensioner bolt was broken off (only a couple threads left on the bottom) Have yet to get a new bolt to tighten the belt properly but did the best i could. The belt now rubs the bottom of the thermostat housing?? Is there a tensioner somewhere else or is the power steering pump the only one? I could be wrong (usually am) but it looks like tightening that bolt will only pull the pump and belt higher making the problem worse. Again any info appreciated.
Ryan
 
Samuryan said:
OK i'm going to ask a question i probably already know the answer to but any info is appreciated. Just changed the rad. on my 88 4.0 xj noticed that the ps pump tensioner bolt was broken off (only a couple threads left on the bottom) Have yet to get a new bolt to tighten the belt properly but did the best i could. The belt now rubs the bottom of the thermostat housing?? Is there a tensioner somewhere else or is the power steering pump the only one? I could be wrong (usually am) but it looks like tightening that bolt will only pull the pump and belt higher making the problem worse. Again any info appreciated.
Ryan
Click to expand...

Nope - the PS pump is the only thing that moves.

Dumb question - are you sure you have the belt routed correctly? I know it's close there, but I've not actually had it start rubbing the thermostat housing on any of my rigs...

Also (another dumb question, but you're going to be looking anyhow) have you checked your harmonic damper lately? The elastomer ring in there can fail, causing the inertia ring to "walk" back and forth. However, that would cause the inertia ring to rub against the timing cover - but it's still something that should be checked periodically...

5-90
 
on your '88 there is the slide on the bottom of the pump that goes through and attaches to a long bolt that pulls the pump towards the drivers fender as you tighten it.
There is also two bolts on the back of the pump. make sure they are just snug when you are tightening the lower one.tighten the long bolt and then tighten the one on the slide, then the two on the back of the pump. (BTW one of the ones on the back of the pump has a tendency to make the pump rise and thats why you are getting too close to the thermistat. ) Mine come close on my '88 but it doesnt hit. Good luck
 
routed per the haynes manual (didn't really seem to be another way to do it) the harmonic damper is on the crank? I'll check it, what do i look for, rubbing on timing cover? I'll get a new bolt for the adustment and see if that clears up the problem. Thanks
Ryan
 
Samuryan said:
routed per the haynes manual (didn't really seem to be another way to do it) the harmonic damper is on the crank? I'll check it, what do i look for, rubbing on timing cover? I'll get a new bolt for the adustment and see if that clears up the problem. Thanks
Ryan
Click to expand...

The bolt that runs crosswise under the PS pump is threaded 5/16"-18 (UNC), is four to five inches long, and is "fully threaded" (if you get a regular bolt that size, it's only going to be threaded for 15/16" of its length.)

Easy way to check the HD - take a ruler and lay it across the face of the thing (yes, it's that large pully on the crankshaft at the bottom.) The hub (inner part) and inertia ring (outer bit) should be flush, and the elastomer ("rubber" bit - it isn't really rubber) should protrude from the face of the thing NOT MORE THAN 1/8". If it fails either of those visual checks, plan on replacing it.

5-90
 
5-90 said:
The bolt that runs crosswise under the PS pump is threaded 5/16"-18 (UNC), is four to five inches long, and is "fully threaded" (if you get a regular bolt that size, it's only going to be threaded for 15/16" of its length.)
Click to expand...
So I can't replace it with a bolt from the hardware store i have to get it from a dealership? Do i need it to thread all the way or is it only threaded at the bottom? Thanks for the help
Ryan
 
Samuryan said:
So I can't replace it with a bolt from the hardware store i have to get it from a dealership? Do i need it to thread all the way or is it only threaded at the bottom? Thanks for the help
Ryan
Click to expand...

Here's the gig - if a bolt is more than three times its own diameter in length (say, for a 1/2" bolt more than 1-1/2" long,) then it will be threaded for only three diameters' worth of it's length unless specified otherwise. Under that, it's fully threaded.

Examples -
1/2"-20 x 1" will be threaded the whole inch.
1/2"-20 x 3" will be threaded for the first 1-1/2", then have a "full-diameter" shank.

However, you can order "fully-threaded" fasteners - but you can't get them from the local hardware store. A fastener house (like Fastenal) or maybe a "tractor supply" store will have them - but a hardware store usually won't.

No reason to get them from the dealer, unless you can't get them anywhere else. Dealer's going to want about four times what it's worth - and you can get them fairly cheaply...

5-90
 
Just returned from Lowes with a 5/16-18 full thread 5" long. Paid 1$ from the specialty fastenrs section. Now to get it on and tighten the belt . . .
 
Yep every city seems to have a nut and bolt place, Although I have never had my adjusting bolt past the 1/2 way point on the threads and that was as tight as the belt will allow on mine at least. If not try yellowpages.com might be the fastest. goood luck.
 
Samuryan said:
Just returned from Lowes with a 5/16-18 full thread 5" long. Paid 1$ from the specialty fastenrs section. Now to get it on and tighten the belt . . .
Click to expand...

That's good info for everyone else - around here, they aren't that common. Glad you found it without going to the dealer!

5-90
 
just in case anyone has a '94 xj with the same busted bolt, mine was 8 mm x 90mm x 1.25 thread. 1.25 at ace hardware. full thread grade 9.
 
acrid said:
just in case anyone has a '94 xj with the same busted bolt, mine was 8 mm x 90mm x 1.25 thread. 1.25 at ace hardware. full thread grade 9.
Click to expand...

Hm - I'll have to find out when that changed. M8-1.25 is often mistaken for 5/16"-16... Fortunately, I know RENIX uses SAE for that screw!

5-90
 
i'm pretty darn sure, i took the collar and the busted bolt in with me, and spent close to an hour b4 i found the right one, now you're making me want to go and double check....:wierd:
 
acrid said:
i'm pretty darn sure, i took the collar and the busted bolt in with me, and spent close to an hour b4 i found the right one, now you're making me want to go and double check....:wierd:
Click to expand...

No - it makes sense that they'd changed (DCX running ISO specs and all...) I'm just not sure if that was in 1991, or maybe around 1993/1994?

5-90
 
well then, i can tell ya at least '94. my experience so far seems to support your 93/94 idea there. i've run into many things that seems to change on my model year - 94
 
The break points for the XJ and MJ usually are...

1986/1987 - introduction of the AMC242I6

1988/1989 - Chrysler bought AMC. Minor electrical changes

1990-1991 - Chrysler introducing their SBEC controller. Jeep went OBD-I

1993/1994 - Daimler/Benz buys Chrysler.

1995/1996 - Jeep goes OBD-II.

1996/1997 - Chassis redesign - interior and exterior changes.

5-90
 
acrid said:
well then, i can tell ya at least '94. my experience so far seems to support your 93/94 idea there. i've run into many things that seems to change on my model year - 94
Click to expand...

Don't feel bad, they made major changes on the 97 TJ's, hood, fenders, grill, dashboard hvac controls, headlight buckets, headlight retainer rings, hood latch, marker lights, turn signals in front, the list goes on. I probably made 3x the trips necessary to the dealer for parts when we rebuilt my sons after he rolled it.
On my 98XJ the owners manual specified 1156 and 1157's in the tail lights, I was bored one nite so I decided to replace all my rear bulbs since one backup had burned out. Followed the owners manaul and bought them all, every one was wrong, all the bulbs turend out to be 3157's that plug and snap straight in instead of having twist sockets, extra trip to the parts store that time too...
 
Took the pump off and pulled the broken bolt end out. It was not a 5/16-18 it is a M8 1.25 and 5" is way too long for that application. Now after going to Lowes again i cannot find this size bolt. FWIW if anyone else is using this thread for info . . . check what you have.
 
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