Binding issue

[hawksoob]

Did a search on this, didn't find a heck of a lot of info, so I'll try with some specifics.

 

Longish trip, 200 miles from Knoxville to Atlanta. 85mph, +/- at 3750 rpm for 3 non-stop hours. When slowing down at the end of the trek, at parking lot speeds, there is a firm binding in the steering when turning (either right or left). Feels like something is blocking the wheel.

 

This ONLY happens after a long trip. Day-to-day driving shows no signs.

 

CV boots have been checked and are allgood and booty. P/s fluid looks good and full.

 

One thing I have noticed: I apparently have a tire issue. I inflate them regularly to 32/31. Recently I have checked them in the morning and RF is 29 and LR is 27. I filled up to said 32/31 right before the trip. Didn't check the next morning, but I'm wondering about the possibility of the tires losing pressure unevenly during the trip, and this causing the binding due to the unevenness, messing with the differential. This, I imagine would be best case scenario. Either buy new tires or, at least, plug whatever tiny leak may be in the offending tires.

 

Any ideas as to WORST case scenario? Bad VC unit? Center diff gone whacko? Go ahead, scare me....

[stant093]

possibally a front wheel bearing getting hot and siezing up? i had one that was bad in the rain and somehow was fine in dry surroundings, eventually it got worse and i had to change it....so maybe a wheel bearing?

[CardinaA]

this an auto or stick car?

[CardinaA]

okay, read your previous post. my car exhibited the exact same symptoms as yours and my regular mechanic said i could proabably get away with driving it for years without a repair. well, the binding got worse (the car almost hopped in tight turns) and i finally decided to have the VC replaced. i found a backwoods transmission guy to do the work (he had done a dozen or so subes) for under 500 bucks, but the dealer will want more like 1500. also, some repair shops will tell you an additive solved the problem with other subarus that have the torque bind, but my understanding is that those cars were probably automatic. unfortunately, i think you might be headed for a VC replacement. The VC is not a serviceable item. I don't know exactly what happens if you don't replace, but i figure you must eventually wear down the transfer case (which picks up the slack when the VC quits). Since I plan to run my car into the ground, I figured it was more wise to do the repair. hope this helps and keep me posted on the details of the prob. it was an unexpected prob and i was a little bothered, but i figure i got lucky not ever having to replace the head gasket or short block like so many other folks with outbacks.

[hawksoob]

It's 5MT. I've read of the toque bind thing, but my understanding is that's ONLY on the 4EAT, right?

 

CardinaA, thanks for the info. I'll see what my mechanic can do for me, VC wise. He's damn good and he already quoted me the oil pump seal leak at about 1/3 of what the stealer quoted me, so I may get lucky with an under $500 job here.

 

I also plan to run my car into the ground. I'm a big proponent of the "get things fixed" philosophy. Not ready to replace him anytime soon.

 

So...that's wheel bearings and Viscous Coupling Unit. Plus, my first assessment of uneven tire pressures (is that even remotely probable?)....Any others?

[Commuter]

Is the resistance in the "steering", or in the wheels/axles/diff? I know that it can be hard to tell.

 

Torque bind usually affects the autos, but it can happen to a manual as well. People have fried the center VC. I read of one case where a guy had 1.5" difference in tire circumference and burned up 3 VC's before they discovered the problem.

 

The VC would seem to be the most likely suspect. I'm not sure just what else you might check. Was any front or rear diff work done recently? Didn't swap out the rear diff with the wrong ratio perhaps? (Slim chance, but thought I'd mention it.)

 

Good luck finding the problem.

 

Commuter

[hawksoob]

Resistance feels to be in the axles/wheels/diff. No work has been done on the diff itself. The only thing that has been done to it in the last few months has been new axle on Driver's side front, 4-wheel alignment, and wheel balancing. As I recall, the first time I noticed this was before any of that. I think it was the impetus for me to have the CV boot checked and, subsequently, the axle replaced.

 

Upon reading a bit about the VC system, I find that there is something about the VC fluid overheating and causing a binding like I describe.

 

I guess the problem is becoming more pinpointed.

Thanks.

[hawksoob]

Interesting ...

 

Just went by my mecahnic's. Scheduled the oil leak repair and asked him about this binding issue. He said that there is a (new, apparently) additive that can be put into the viscous coupling fluid to help lubricate the clutch mechanism therein. Should take care of the problem. $40!!!!

 

Fingers crossed .....

[myles]

Originally posted by hawksoob

Interesting ...

 

Just went by my mecahnic's. Scheduled the oil leak repair and asked him about this binding issue. He said that there is a (new, apparently) additive that can be put into the viscous coupling fluid to help lubricate the clutch mechanism therein. Should take care of the problem. $40!!!!

 

Fingers crossed .....

 

The viscous limited slip unit is _sealed_, repeat, _sealed_. If/when it breaks, you replace it. There's no way to add anything to the silcone fluid inside.

[myles]

Originally posted by CardinaA

okay, read your previous post. my car exhibited the exact same symptoms as yours and my regular mechanic said i could proabably get away with driving it for years without a repair. well, the binding got worse (the car almost hopped in tight turns) and i finally decided to have the VC replaced. i found a backwoods transmission guy to do the work (he had done a dozen or so subes) for under 500 bucks, but the dealer will want more like 1500. also, some repair shops will tell you an additive solved the problem with other subarus that have the torque bind, but my understanding is that those cars were probably automatic. unfortunately, i think you might be headed for a VC replacement. The VC is not a serviceable item. I don't know exactly what happens if you don't replace, but i figure you must eventually wear down the transfer case (which picks up the slack when the VC quits). Since I plan to run my car into the ground, I figured it was more wise to do the repair. hope this helps and keep me posted on the details of the prob. it was an unexpected prob and i was a little bothered, but i figure i got lucky not ever having to replace the head gasket or short block like so many other folks with outbacks.

 

Do the viscous limited slips typically fail "locked", or "open"? I wonder how many of us are driving around with "open" diffs w/out realizing it.

[hawksoob]

Originally posted by myles

The viscous limited slip unit is _sealed_, repeat, _sealed_. If/when it breaks, you replace it. There's no way to add anything to the silcone fluid inside.

 

OK. Confused. Is "viscous limited slip unit" particular to LSD or to all AWD VC systems. I don't have LSD.

[myles]

Originally posted by hawksoob

OK. Confused. Is "viscous limited slip unit" particular to LSD or to all AWD VC systems. I don't have LSD.

 

In the North American market, _all_ Subarus with manual transmissions, except the WRX STI, have a center differential with a viscous limited-slip unit. Some also have LSD's on the rear axle.

 

Think of it this way: your center differential is built like a normal, open differential, but the shafts that transmit torque to the front and rear axles are joined together by the viscous coupling. When one shaft is turning considerably faster than the other, the silicone fluid (that's sealed inside) will begin to shear and heat up. The properties of this fluid are such that it becomes more viscous with increasing temperature. This "locks" the two shafts together (for suitably generous definitions of "lock").

[CardinaA]

i agree with myles re the lack of servicing issue of the VC. I would be very wary of any "magic fluid" because i searched high and low and talked to lots of mechanics, eventually deciding, based on the opinions of the most knowledgeable mechanics i know, that the VC could not be serviced. like i said in my first post, i think the treatments are mostly for the 4EAT with torque bind. Even if you could add replacement fluid, i would think you already have down irreversible damage to the existing VC. the fluid has either had a change in viscoscity or is completely fried. i wouldn't add oil to a seized engine thinking i could just crank the sucker up with no problems down the road.

[myles]

Originally posted by CardinaA

i agree with myles re the lack of servicing issue of the VC. I would be very wary of any "magic fluid" because i searched high and low and talked to lots of mechanics, eventually deciding, based on the opinions of the most knowledgeable mechanics i know, that the VC could not be serviced. like i said in my first post, i think the treatments are mostly for the 4EAT with torque bind. Even if you could add replacement fluid, i would think you already have down irreversible damage to the existing VC. the fluid has either had a change in viscoscity or is completely fried. i wouldn't add oil to a seized engine thinking i could just crank the sucker up with no problems down the road.

 

The fact that the viscous unit is _not_ serviceable is spelled out in the factory service manuals :-)

[hawksoob]

Many thanks. Maybe he hasn't worked on my car enough to remember whether it's a 5MT or 4EAT and he's thinking the torque bind.

 

OK...there go the hopes of the cheap fix.

 

Thanks, again.

[hawksoob]

Well, mechanic talked to Subaru. Told them the whole issue and which car I had. Subaru told him about the additive. $7.50. Added with new round of tranny oil.

 

Will see what happens after the next long trip.

 

:\

[Chip]

I had the same problem in my 98 O/B...I expected the worst and finally realized it was corrosion in the steering column u-joint. A couple shots of WD-40 and things were fine.

The U-joint is about a foot down from the firewall.

[hawksoob]

Seems to be many different causes for this, the more I research it, leading to much more confusion and more theories and possible fixes. When it happened the other night, before my repair work, it was NOT after a long trip. Just around the corner to the store. It was pretty bad. When I got home I realized that my RF tire was about 8psi lower than the rest. I'm really, now, thinking the tire with the leaky valve stem is the cuplrit in this. The 3 hour trips just allow time for the slow leak to get to the point that that one tire is completely off whack, causing the center diff to whackless, as well.

 

Here's to hoping.

[vladhed]

Thanks for all the information on this.

 

I have the exact same problem on a 95 Brighton, 5MT, and have it in today for the 168,000km maintenance and ask them about it.

 

I just got off the phone with the tech who explained that the VCD is worn out, and will cost 960$+4hrs (1300$ Canadian) to replace!!!

 

So I said, "what if we just leave it?"

 

He said it would eventually wear to the point that I essentially had 2WD - though I think he means that the centre differential would essentially be an open differential, but that there would be no adverse affect on other parts of the drive train.

 

He tried to describe the VCD as this "3-in wide disk with a big gear on it", and over time a groove is worn in the disk - ?? anyone got a picture :-)

 

As long as I don't mind driving and AWD car with an open centre differential, I don't have to do anything.

 

I'm not doing anything :-)

 

cheers!

[Commuter]

The How Stuff Works sight gives a good overview of the viscous coupling. http://auto.howstuffworks.com/differential9.htm

 

 

Commuter

[vladhed]

Ah, I'd seen that before but didn't understand it. Does the vcd thing shown in http://auto.howstuffworks.com/differential9.htm basically fit between the front and rear shafts in the middle of an open differential?

 

(see attached)

[hawksoob]

FWIW:

 

I just read on an Australian site re: VC units-

 

There are major differences between those VCs found in vehicles built before and after the MY99/Version 5-6 STi. Earlier models have a circlip on the coupling, which - when removed - allows the housing to be split and the VC cartridge to come out and to be disassembled. Post MY99s - with their stronger, 6-bolt gearbox housing - have a sealed VC assembly that's impossible to open and repack. The viscous liquid in these couplings, incidentally, is said to be very tacky and smelly.

 

http://www.mrtrally.com.au/performance/viscous_coupling.

[hawksoob]

Curious: It may have been mentioned before:

 

I was poking underneath my car the other day and noticed 2 things. The most obvious being a rubber gasket of some sort seems to be coming out of the steering shaft (?) Rod? axle? (not CV axle. I know what that is.) Also, I noticed a reddish non-oil looking fluid hanging out around the cross member and behind. Dripping a bit. Assuming power steering fluid. May be a stupid question, but could a leaking power steering line cause this problem? And only after extended driving. I'm giving the blame for the clunking sound to the loose gasket and that for the gindy/bindy when turning to the power steering line leakage. Plausible? I checked the fluid level but it's very difficult to check a nearly transparent fluid on a black, shiny plastic stick. But for an idea, after being driven a bit, the fluid is about an inch below the top of the reservoir.

 

Also, any ideas what it may cost to fix a leaking PS system?

 

 

Thanks.

[vladhed]

When you originally said "Feels like something is blocking the wheel.", did you mean a wheel on the ground or the steering wheel? Based on the comments that followed I assumed you meant the former. Based on your last post, now I think you mean ther latter.

 

With my car, the steering wheel moves freely, but the rear outside wheel wants to slip when going around a tight corner (e.g. parking spot) - so if feels as if someone was pressing on the brakes and I need to give it some gas to overcome either the resistance in the VCD (dry pavement), or slip the outside back wheel (on gravel).

 

Sounds now like you problem is with the power steering.

[hawksoob]

It's entirely possible that the two problems are indedpendent of one another. The original post WAS in reference to a binding in the wheel, like you describe in yours. However, when I first posted over on NASIOC, a couple of posters asked about the power steering pump or the PS fluid level. That just didn't seem right to me, especially since it seemed to be a heat think. If the PS fluid was low it would do this all the time, right? It only does it after extended driving. Recently, when doing a search here on PS fluid leaking, some of the threads started out mentioning a similar issue, and the answers from some were "check your PS fluid level" and the like. My thought was, also, that if there is a HOT and COLD indicator on the PS fluid dipstick, then perhaps whatever route the fluid must take in order for it to rise in its level may be thwarted somehow ... perhaps by this leak. The car gets nice and warm and suddenly the PS fluid is lower than it should be. Just a thought, since I really don't know the mechanics of that system.

 

Anyhoo, I'm just trying to narrow stuff down before I shell out a grand or more and not actually get the problem fixed. I'd like to go to the mechanic and say, "This is what's happenening, please check it out, I've noticed ______, and ______, and_______. Any other ideas?"