Too much vibration with brakes applied in DRIVE at stoplights.

[Legback]

It seems to be getting more intense. There is no vibration at all when I let go of the brakes. The moment I reach a dead stop, this serious vibration begins. It's bizarre. Could a brake line be rotted out somewhere or another component be crapping out? It is a 98.

[bratman18]

Sounds like your rotors are warped to me. I see you're from Maine!!

[tcspeer]

It probably dont have anything to do with the brakes. When you stop and it shakes leave your foot on the brakes, and then shift to neutral it will most likely stop that way also.

 

I have been around this board a few years and have seen this question come up many times, with no answer from anyone that has been a cure all. My 97 legacy 2.2 still does this.

 

I think the problem comes from the idle air control, some think it comes from axles that have been changed. Others think many other things.

 

At one time I sparyed carbarator cleaner into idle air control valve and it seemed to help some. If you will do a search on this you should get a few ideals to try. If you find the cure please post for all of us to see.

[Fairtax4me]

This is a common problem on many 4 cylinder engine vehicles. To an extent it is considered normal on many cars, Saab, Toyota, VW, anything with a 4 cyl engine, most of the time FWD, but some RWD cars will do it as well.

Most of the time (when excessive) it can be attributed to incorrect (too low) idle speed. Cleaning the intake and idle control system may help.

 

It can also be caused by incorrect cam timing. A worn/stretched timing belt/chain can cause the timing to be off by just enough to create problems at idle.

 

Ignition timing is another cause of this, but the ECU controls the timing on all modern cars. No adjustment there. You can check it to see if it is out of spec, but that's really kind of pointless.

 

I fail to see how an axle would cause this, unless it's flat out broken. The axles don't move when the car is sitting still. No movement, no vibration.

[daredevil1166]

I fail to see how an axle would cause this, unless it's flat out broken. The axles don't move when the car is sitting still. No movement, no vibration.

 

Me too. But it's apparently a common problem with aftermarket axles.

 

Do a search on subaruoutback.org. It comes up there quite often.

 

Legback.... First thing you should do is note the idle RPM's when stopped and the car is vibrating.

 

If they're low, it tells you it's an engine problem. If it's normal it would be somewhere else in the drivetrain.

[Ionlyhave3suubs]

With regard to the axles and vibration. I have replaced the front axles on my 96 Lsi Legacy with aftermarket pieces. They do seem to vibrate more than the oem ones, but only while the car is in motion. It is especially noticeable under hard acceleration.

 

I don't know of any reason why axles would have anything to do with vibration on a stationary vehicle since they are not in motion. I suspect some aftermarket axles are not as well balanced as oem units, thus the vibration while in motion.

 

As far as a vibration while the vehicle is stopped, my first thing to check for would be a vacuum leak. Vacuum leaks will cause this sort of rough idle/vibration.

 

Any recent work done to the engine?

[Legback]

I've been messing with my throttle cble nuts and maybe I confused something. should I try unplugging my battery for a few hours to see if the sensors reset? It's only in DRIVE STOPPED(motionless). Can't be a shaft. I did my own timing belt so maybe I F'd it up. It runs suspiciously smooth otherwise. By brake parts going I was thing mastr cylnder or smthing. Does the engine power the brakes at all or is it totally closed? Car idles perfectly in park.

[Ionlyhave3suubs]

Check engine light on?

 

Disconnecting the battery will re-set the ecu. Doesn't take hours though. Won't do anything for you if the check engine light is not on though.

[Ionlyhave3suubs]

A bad power brake booster can cause these symptoms. A hole in the diaphram creates a vacuum leak which causes rough idle which will be more noticeable at low RPM. Depressing the brake pedal actuates the diaphram which opens the leak, causing the rough idle condition.

 

To test and see if you have a problem there, disconnect the hose going from the intake mainfold (at the manifold end) to the power brake booster. The hose connects right beside the EGR (if so equipped) otherwise to the back of the intake manifold, toward the driver's side of the throttle body. After disconnecting the hose, cap the fitting that you disconnected the hose from. start the engine and see if you still have the same rough idle. You can try depressing the brake pedal, but since it is not connected to vacuum, the power brakes will not work now.

 

If that eliminated your vibration, your problem is most likely going to be either a bad hose going from the intake to the brake booster, or a bad brake booster. Inspect the hose first for cracks, tears, holes, etc. as this is easiest to see and cheapest to replace. If the hose is good, I would strongly suspect the booster. Often bad boosters will hiss or make a sucking sound when you apply the brakes.

[daredevil1166]

I don't know of any reason why axles would have anything to do with vibration on a stationary vehicle since they are not in motion.

 

That's cool. I'm an idiot. Don't listen to me but take a look at this if you could.... especially post #15

 

http://www.subaruoutback.org/forums/66-problems-maintenance/24013-vibration-when-stopped-gear-2.html

 

And why diagnose a rough/low idle when you don't know he has it?

 

Kudos for trying to help him, but you're assuming it's an idle issue when he hasn't even taken note of the idle.

Edited January 18, 2011 by daredevil1166

[Fairtax4me]

I'm going to read up on that axle stuff tomorrow. Incorrect axle length is an interesting theory. I just can't concentrate on it enough to read through the multiple threads right now. Need to make a few of these first... zzz

[NoahDL88]

+1 on the vacuum booster, plug the hose and see if the idle is smoother.

 

 

Anything stationary on the car won't be the problem, except for possibly the engine mounts, but those rarely fail, but checking can't hurt once you've ruled out the vacuum booster.

 

Axles? really guys, probably not.

[CNY_Dave]

I'm going to read up on that axle stuff tomorrow. Incorrect axle length is an interesting theory. I just can't concentrate on it enough to read through the multiple threads right now. Need to make a few of these first... zzz

 

I've been looking for good evidence on whether its the axle too long and it bottoms (no necessarily horrible since the rest position has the axle in its shortest position), or if the inner CV joint is assembled too tightly and there is a bit too much force (more likely stiction, like on a motorcycle fork, rather than once it slides it slides too tight) transmitted down the length of the axle when the joint just starts/stops sliding (which it is always doing as the motor vibrates).

 

Dave

[Fairtax4me]

Axles? really guys, probably not.

 

I'm still skeptical, but I don't think we can discount the fact that multiple people are having problems with excessive vibration when sitting still after replacing axles.

This seems to be limited to only automatic transmission vehicles. So maybe it has something to do with the axles being under load? Gonna ask some of the guys at the shop if they've heard of anything like this.

[Legback]

Havn't had a chance to plug the vacuuum jose yet. This isn't happening at every stop. It's only some of the time so if it is a hose, it's just barely cracked maybe. I DID just install GL-S from Advance drive axle a couple weeks ago. I can't believe it bouncing around while stopped just due to normal engine vibration. There is no engine vibration normally. Must study further.

[Legback]

I see you're from Maine!!

 

Cheers, Bratman. The great north. Having a good snowstorm? That moisture component is making for some slick Soobin' down he-ah! (that's "here" to the rest of you)

[NoahDL88]

I don' know if these cars also have a lockup torque converter, if those are sticking, or not retracting all the way then they can cause the same symptom as well.

[nipper]

It seems to be getting more intense. There is no vibration at all when I let go of the brakes. The moment I reach a dead stop, this serious vibration begins. It's bizarre. Could a brake line be rotted out somewhere or another component be crapping out? It is a 98.

how many miles

when was the last tuneup

whenwas the airfilter last looked at

are the axles original

[Fuzpile]

I had a problem similar to this. i thought the ABS pulses were coming on at idle stops and i did have that motor running sound all the time. This has abated since my last brake bleed. I now have a decent pedal. This may be related to air and the depth to which the pedal travels, activates the ABS ... Anyway the information from ionlyhave3 is particular great for it explains how it may seem this way.

[Legback]

The left front axle is not original. IT has 163000. I replaced seals Tbelt idlers etc 1500 miles ago. Plugs and wires about 3000 miles ago. It has to be related to the brakes. Topped off brake fluid and I'm watching the level. Would the calculated Load% on my scantool help determine anything in terms of how much the brake system is taxing the engine?

My brake fluid is 50% old. Maybe I should bleed/change brake fluid? Cold dead brake fluid.

[nipper]

Vibration in drive

Axle

replacement Axle

Replacement Joint

 

(that was all done for the search)

 

How in heck can it be related to brakes when stoped? If you do not want to listen to us, and ignore all the threads on this subject, feel free to throw money at your brakes.

 

Check the tronsmission mounts.

 

How old is that replacement axle and where did it come from.

 

 

Since you have not used the search, I will explain it one more time (I wonder if this is a sticky) but not in great detail.

 

Axles are rebuilt all at once in a factory. They tear things apart and throw them in one crate for processing. They check the dimensions without really knowing tolerances. The cages and balls are replaced at this time, and again, they do not really check tolerances. This affects the required free play to keep the engine vibrations to be transfered to the car.

 

Why in drive?

 

Because in drive the drivetrain is connected to the engine's torque through the transmission and transmits the engine vibration through the axle to the car. Side to side mount engines do not do this because they rotate around a axis in the drivetrain. On a subaru or anyother for-aft FWD car, the rotation of axis is 90 degrees from the driveshaft so it can not freely shake in a way that it can move freely. Some axles are better then others. Autozone uses the same rebuilder as subaru does for axles that they do not rebuild anymore. They are done in mexico but the do subaru axles aside from other axles.

 

This does not happen in manuals or in neutral.

[NoahDL88]

Seriously, you think that brake fluid is creating a vibration from your engine?

 

I've got ocean front property in Kansas that i'll sell you cheap.

 

 

Brakes vibrate because they are out of round, a condition that is related to speed, if they are stationary they will not vibrate, or cause vibration, period, end of story, Fineto.

 

Try using the parking brake, its a load issue on your drivetrain, and should, no, I'll say will not change when you just use your parking brake.

 

Anyway, its a load issue, there is a vibration that is either caused by or effecting your engine. It is not uncommon for an engine with problems to vibrate more at idle then when at higher RPM, it could very easily be the timing belts or the ignition components that you replaced, either you didn't tighten all the bolts or you got a bad plug or wire.

 

If its not the engine it could be a mount, engine or tranny, I had a friend who's car would always stall on hard right turns, his left engine mount was torn in two and the engine would flop over and kink the fuel line.

 

It could also be an issue in your transmission, sticking solenoids could be putting a load on your engine and causing the engine to over compensate to maintain proper idle speed.

 

 

Seriously, If its not a moving part, it is not the issue, but it is your car, so if you know better than us and want to do whatever you want go for it, I just don't understand why you came here asking for help if you're going to ignore our suggestions to save you time and effort, and in the long run money as well.

[WoodsWagon]

Noah, there often isn't an actual engine problem to cause the vibration. The stackup of tolerances in a worn or shoddily rebuilt axle let the power pulses of the engine vibrate the car, and replacing the axles can often make the issue go away.

 

The real problem is that the torque converter stall speed was designed too low, so the hydraulic coupling at idle speeds is too strong. If a higher stall torque converter was used, it's connection at idle speeds would be much "looser" and the power pulses wouldn't be transmitted through.

 

The brakes are not the problem, the mounts are not the problem, and nothing is really "broken". The vibration is a mild annoyance, and clicking it into neutral when sitting stopped will make it go away. You can push the shifter into neutral without depressing the thumb button so there's no risk of going into reverse on accident. My mom's been doing that for years with her Outback. It's a "design feature" of the too-tight converter. Not an actually problem or failure per say.

 

Buicks, Olds, and Cadillacs of the mid 60's had "switch pitch" torque converters, that had a variable stator blade angle. It would switch between a high stall and a low stall torque converter. They switched into high stall when the throttle was closed in the idle postion to uncouple the engine from the drivetrain, to eliminate this exact vibration problem. The converter was then switched to low stall as soon as throttle was applied to keep the engine RPM's low and the fuel economy better. If you planted the throttle wide open, it would switch back to high stall to get the engine up in it's peak torque rpm range.

[tcspeer]

91Loyale,

 

I dont know is what you said is correct but I really like that answer. This topic has been brought up many times over the years and this seems to be solid information.

 

I have had this problem with my 97 2.2 and if I shift up to neutral at the stop lights it also will stop shaking. I would think if it was a engine problem this would not make it go away.

 

Edited in after above!

 

After back reading some posts here I see Nipper & Noah have also touched on this, so I give credit to all three of you. And anyone else if I missed it.

Edited January 20, 2011 by tcspeer

[Legback]

Vibration in drive

Axle

replacement Axle

Replacement Joint

 

(that was all done for the search)

 

How in heck can it be related to brakes when stoped? If you do not want to listen to us, and ignore all the threads on this subject, feel free to throw money at your brakes.

 

Since you have not used the search, I will explain it one more time (I wonder if this is a sticky) but not in great detail.

 

 

 

You rock Nipper:headbang: I guess I deserve a lump, however, I wouldn't have used those search words.

Vibration while stopped yielded essentially the exact same question and mine.

I could hardly believe that the same 25 suggestions were on that thread too! My axle is from ADVANCE AUTO PARTS. A GL-S chinese turd. Get a Subaru one?

Thanks for taking the time to re-explain.