Possible rear diff issue??

[phil.allchurch]

Hi everyone,

 

I went to reverse my car out of the driveway and it just won't budge, i could tell by the suspension movement that it's the rear that is the issue, so I jacked the car up and tried to spin the right rear wheel forward then backward.. it moves a fraction then just locks up.. same with the left hand side.. Don't know too much about cars but i'm guessing it has something to do with the rear diff? If so, will this be an expensive fix? and how do I go about getting it fixed??

 

Cheers Phil

[idosubaru]

could it be the emergency brake sticking, misadjusted, or (around here lol!) rusted? that seems most likely.

 

if you really suspect the rear diff - drain the fluid and inspect carefully for chunks/metal etc.

 

i doubt it's your rear diff, but boards like this do bring all sorts of crazy things! rear diff failures are very rare and i wouldn't expect this without some kind of prior signs, noises, etc. a failing front or rear diff that doesn't make noise would be surprising to me.

 

auto/manual?

year/miles?

 

when spinning the wheels did you:

did you jack the entire car off the gound?

or just two wheels off the ground - if so which two?

 

it was running perfectly fine with zero issues ever yesterday, then you parked it and it wouldn't move?

[phil.allchurch]

Na well if it was the handbreak sticking the wheel wouldn't budge at all, but yeah there is a bit of a rust, and has built up surprisingly quickly over the past week when i backed down the boatramp into salt water. wouldn't think it was the handbrake as i'm able to move the wheel a little then just stops, feels as if its a mechanical stop, not just like the pads rubbing and coming to a halt.. na no noises at all that i've noticed.. It is manual, 2001 and 111000ks so not terribly old.

 

ok this is where i've made a wee slip up.. just 1 wheel jacked up, i'm guessing the rear wheels move in sync??

 

Yeah haven't used it in a week and last time i did use it the rear wheels were in sea water.. but i did give the wheels a spray with the hose

[idosubaru]

i turned a rear EJ automatic by hand a week ago, but i feel like i've had some before that would not turn if only one wheel was off the ground?

 

seems like it wouldn't happen that quick but i'd still be curious if rust built up enough to prevent the ebrakes from clearing and they're keeping it from turning. i saw one legacy locked up in the rear due to rusting while it sat and i never looked at it before they got rid of it so i'm not sure what caused it.

 

could the rear diff have filled with water?

 

is this an open rear diff or VLSD?

 

rear diff is definitely something that affects both sides so that's a good place to look if they are locked.

[edrach]

Jack up the back end (BOTH wheels off the ground) and try the test again. An open diff: turn one wheel and the other should turn in the opposite direction. Limited slip diff: opposite wheel will turn in the same direction. If it stll won't turn, make sure the car is properly supported and disconnect the driveshaft from the front flange of the rear diff. Only four bolts. If it still won't turn, either the diff is frozen (pretty rare failure) or the handbrake is keeping the wheels from turning.

 

If you had the rear of the car under water (salt water to boot), you might have gotten some water inside the diff (there's an air vent at the top which would allow water inside). If you got water inside, I could understand the rear diff seizing up. Check the rear fluid by making sure the FILLER plug is not seized and then drain out the oil through the drain opening; hopefully there's no water in there with it. Re-fill the diff with 75W90 gear oil and hope for the best.

 

Worst case, you have a bad rear diff. Just replace it with one from a wrecking yard. Our local pull a part yard will sell them for around $40 with a 30 day guarantee. Just make sure you get one with the correct ratio (most likely 3.900).

[nipper]

Info we always need, modle, engine, transmission, mileage.

 

With both rear wheels off the ground you should be able to turn one and the other will either not turn or go in the other direction. It may not turn only because of drag from the brakes (disc pads). Do you have room to try to go forward?

[1 Lucky Texan]

Jack up the back end (BOTH wheels off the ground) and try the test again. An open diff: turn one wheel and the other should turn in the opposite direction. Limited slip diff: opposite wheel will turn in the same direction. If it stll won't turn, make sure the car is properly supported and disconnect the driveshaft from the front flange of the rear diff. Only four bolts. If it still won't turn, either the diff is frozen (pretty rare failure) or the handbrake is keeping the wheels from turning.

 

If you had the rear of the car under water (salt water to boot), you might have gotten some water inside the diff (there's an air vent at the top which would allow water inside). If you got water inside, I could understand the rear diff seizing up. Check the rear fluid by making sure the FILLER plug is not seized and then drain out the oil through the drain opening; hopefully there's no water in there with it. Re-fill the diff with 75W90 gear oil and hope for the best.

 

Worst case, you have a bad rear diff. Just replace it with one from a wrecking yard. Our local pull a part yard will sell them for around $40 with a 30 day guarantee. Just make sure you get one with the correct ratio (most likely 3.900).

 

^^^^

I'm guessing this is what happened. And, if the diff was still warm from driving, getting the vent under water is even worse cause, the water will start cooling the diff creating a little suction - so even more water gets inside.

 

But, did the driveshaft rotate at all? Need to try in neutral with both rear whhels off the ground as said.

Edited December 11, 2011 by 1 Lucky Texan

[phil.allchurch]

Problem solved!!! Was the brakes rusted to the discs. A few revs sorted it out. I sprayed the disc with a bit of crc to remove some of the rust yesterday, looks better today. Took it for a drive to get some of the residue off the disc.. Appreciate your help guys, really appreciate it

[1 Lucky Texan]

Problem solved!!! Was the brakes rusted to the discs. A few revs sorted it out. I sprayed the disc with a bit of crc to remove some of the rust yesterday, looks better today. Took it for a drive to get some of the residue off the disc.. Appreciate your help guys, really appreciate it

 

 

wow! glad it was that easy. I guess the slight movement you saw was the pads shifting a little in the caliper? crazy

 

I'd put a complete rear brake tear down,inspect,clean, lube job on my to-do list if I were you. Don't want those slide pins or the e-brake corroding.

Edited December 12, 2011 by 1 Lucky Texan

[idosubaru]

awesome, easy fixes are awesome. no rear diff issues, that's good news.

 

that's why it was my first guess. there's likely some rust ridges and what not up around those brake shoes for the ebrake. like the part of the rotor that isnt' connected to the shoes, it'll continue to rust around and right up to the shoes as there's nothing thtere to "clean" them so to speak.

 

thsoe inner brake shoes aren't really accessible much by spraying off with a hose, they're inside the rotor if you know what i mean. not a good set up for getting salt water on them.

[idosubaru]

I guess the slight movement you saw was the pads shifting a little in the caliper? crazy

that's pretty typical for them to have a tiny bit of play. i think the rust builds up "around" the ebrake shoes and boxes it in so to speak, so you can wiggle it back and forth as it runs into rust ridges, etc and breaks it down, etc until with enough time/effort it pushes through it.

[phil.allchurch]

Yeah thats what would've happened, but the crc spray broke the rust down enough overnight, and just reversed the car with a few revs and that sorted it. So you'd recommend getting the brakes checked out?? Cos like you say there is a bit of rust build up around the brakes..

Edited December 12, 2011 by phil.allchurch

[edrach]

Problem solved!!! Was the brakes rusted to the discs. A few revs sorted it out. I sprayed the disc with a bit of crc to remove some of the rust yesterday, looks better today. Took it for a drive to get some of the residue off the disc.. Appreciate your help guys, really appreciate it

You might check the gearoil in the rear diff anyway. Even a little water might not be good for it. Glad to hear it was the brakes.

[unibrook]

Just to add some info on this topic. 2001 Forester 111,800 miles on her.

No symptoms, but decided to change the rear diff gear oil, since I doubt previous owner ever did. Drove car to get it warm. Put rear wheels up on ramps to get swing room to apply about 50 ft-lbs on the .25" breaker bar to loosen the fill and drain plugs...in that order. The old oil came out looking like a caramel milk shake. Lots of fine black metal powder shavings around drain plug magnet. Refilled with .80 qt of Lucas Synthetic 75-90 Gear Oil. $13.80 per quart. You pretty much can't overfill it, since oil will start dribbling out of the fill plug hole when it is full.

[jdemaris]

Hi everyone,

 

I went to reverse my car out of the driveway and it just won't budge, i could tell by the suspension movement that it's the rear that is the issue,

 

All three of my Subarus and my Kia Sportage will do that just about any time they're parked on wet ground and sit for a week. No big deal. I just rock back and forth a few times until the brake pads break free. When brakes get stuck, regardless if pads, shoes, or parking-brake shoes - there will always be a little back-and-forth free movement. That because of slop in the caliper mounts and the shoe hold-down pins.

[idosubaru]

So you'd recommend getting the brakes checked out?? Cos like you say there is a bit of rust build up around the brakes..

 

not necessarily, hard to say without seeing it. for it to be a problem either the caliper slides would need to be out of grease or the pad clips would need to be rusted/corroded.

 

the rusting/seizing like you experienced isn't an immediate indication there's a real issue....but i can't say there isn't one either. if the brakes are functioning properly now that's a good sign they're okay though.

 

you can visually watch the calipers as someone presses the brakes - if one is seizing you'll notice it "clamps" different than the others. so you can just watch the calipers from under the car while someone stomps the pedal for you. i just did this to a 2005 Buick last week, seized caliper pin the caliper would "rock" rather than clamp. quite obvious even to someone that's never done it before - it was notable different than the other side.

 

if you got a really good, nice mechanic, then probably easy enough to try out. if you're at the whims of any old joker wanting to make some quick cash i'd probably pass.

 

personally i have found it helpful to have an entire brake hardware kit on hand for my next brake job so it's got new clips and boots. the clips corrode and hang the pads.

 

with places like rockauto i've gotten the hardware kits for like $5-$10 for both sides, well worth it.

[jdemaris]

n

 

the rusting/seizing like you experienced isn't an immediate indication there's a real issue....but i can't say there isn't one either. .

 

I've found that when the rotors get worn and a little pitted, they rust faster when parked and get stuck to the pads. Happens often with most of my winter cars.

 

I suspect if brakes started sticking like that on a daily driver, I'd look for other problems. Not for something that sits though.

 

We take two of our Subarus off the road every spring and summer. Always when Fall comes and I want to drive them again, at least one wheel and often two will be locked up tight. Sometimes so bad I have to yank the wheels off and take it apart to get it free. This Fall I got lazy with my 95 Impreza that had two rear wheels locked up tight. I just kept punching the gas and tried to rocking it back and forth. It finally broke loose but the brake pads actually broke off the steel plates they had been glued to. I actually had to take a chipping hammer to the rotors and knock off a layer or rust before I put new pads in.