subaru forester shock failures (leaking)

[jondsw]

hi, i have a 2012 forester and the dealer told me that the rear shocks are leaking. can anyone tell me if towing a scamp 13 might tend to cause this problem, i.e. by putting more forces on the shocks that they were designed to handle?


thanks for any info/advice


jondsw
of sequim

[sokhapkin]

I don't think it is related.

[Mike Magee]

Probably not, but why do you ask? Surely they are long out of warranty, and shocks are not that expensive. Buy new ones and keep on traveling!

[thrifty bill]

Maybe if your trailer’s axle is worn out (lots of bounce), or perhaps poorly loaded (lots of sway). It’s all speculation.

Or perhaps if your Scamp 13 is fully optioned out. Not all Scamp 13s are light weight. What’s your tongue weight? It’s pretty easy to exceed the tow capacity of a Forrester.

[Jon in AZ]

I believe we're talking struts here, not simple shocks, so replacement is not trivial.

Even so, struts are normal wear items. Lifespan varies greatly depending on use. The roads you drive, climate, driving habits, and yes, towing can affect strut life. FWIW the rear struts on my '93 Legacy required replacement at 120K miles, and there was no towing.

Even a basic Scamp 13 carries around 200 pounds on the hitch, right at the limit. Add any cargo in the vehicle and you're probably over, at least a little.

Did that cause the failure? Probably not by itself. Could it be one factor among others? Sure. Towing is considered severe use of any vehicle, and you can expect more frequent maintenance on drivetrain and chassis components.

Fix it and move on. Console yourself with this: it's a lot cheaper than a new vehicle!

[ZachO]

I know if I didn’t have air bags in my rear suspension, my trucks rear springs would be bottomed out with my trailer connected. That’s partly because my leaf springs are shot, but a combination of that and one of my air bags getting a hole in it caused a rear shock to start leaking. Weak leaf springs, no air bag on that side and a couple days of my trailer hooked up was all it took.

200lbs is really just a normal size American at this point so I agree that wouldn’t be the only factor, but it would definitely be one of them.

[Spongelander]

How many miles on the vehicle? On what general terrain? Quite conceivable they are just worn out. They are struts, meaning shock inside coil spring. All that means is that it's a bit more complex than pulling four nuts or bolts and swapping shocks out. Instead, the strut assembly needs to be pulled, the coil spring compressed, removed, and transferred to the new shock, then tension released and strut re-installed (new shock/existing coil spring). So a bit more cost than just the shock.

[Mike_L]

Likely a contributing factor but shocks/struts are a wear item.

[ZachO]

Re-reading the initial post I'd say:

Yes, hauling even a 13' Scamp is more weight than Subaru probably really intended for the vehicle, especially if you're already loaded down with a bunch of camping gear. But as people have mentioned, struts and shocks are an item that wear out with time no matter how little weight you carry.

It's important to remember than any towing should probably be considered "heavy duty" use. I don't remember the exact terminology but I remember that in the aftermarket repair manual for my vehicles, there is a maintenance schedule. There were different timelines for checking, replacing, changing fluids, belts, shocks etc. depending on "light duty" of "heavy duty" use, or something like that.

Towing is going to take a toll, which is why many people choose to go with overkill for a tow vehicle. When you're towing at your limits, which you almost always are with a car or truck that wasn't really meant to tow in the first place, all the parts of the vehicle requiring regular or occasional maintenance or replacement are going to need those thing sooner than if you didn't tow.

So, it's to be expected. You'll go through shocks, struts, brakes, engines transmissions and clutches faster if you tow a lot. Just the way it is.

[John in Santa Cruz]

btw, 'shock absorber' is actually a poor name, the english term is 'dampers', and thats really what they do, they 'dampen' the motion of the suspension. most automotive shocks are designed to have fast compression, and slow on the rebound, so when the wheel hits a bump, it can go up quickly, but is slowed on the way back down, this prevents the suspension from bouncing or pogoing. ideally, this damping factor is tuned to the spring rate... you do NOT want really stiff damping with a soft spring, or your suspension can get compacted down on a series of fast bumps, like washboard. better shocks often have separate values for slow and fast damping, done with internal valving.

my general experience with Toyota and such cars is, the factory shocks are barely adequate when brand new, and by 50000 miles are pretty much shot, and thats not even towing, just regular driving. On my European cars (I've owned a series of vws, volvos, mercedes over the years, put high miles on many of them), the factory shocks were generally Boge/Sachs, and would last a lot longer than the KYB's I've found on many asian vehicles. Ditto, Bilstein shocks generally last a lot longer (but are often stiffer, depending on the model and application).

a car regularly used for towing, you might investigate to see if 'heavy duty' or 'overload' springs are available for the rear suspension(*), and use these in conjunction with a heavier duty or sportier shock, this will give you a somewhat harsher ride in the back when you're running around empty, but will handle the full load of a trailer + gear much much better. I've done this on older Volvo wagons with great results.


(*) if the vehicle has some sort of self-leveling suspension, then tread with great care here. my wife's 1994 Mercedes e320 wagon has a very nice SLS self leveling system, and automatically adapts to the rear load firming up both the spring rate AND damping when heavily loaded, so the car rides as well loaded as empty.

[redbarron55]

Just put new ones on and then get the car realigned.
Here is one choice of a loaded rear shock strut which means that it already has the speing mounted so it is just a remove and replace item.

https://shop.advanceautoparts.com/p/...FYx2wQodOj8AcA

The next point is that "sometimes" a nice shot of oil from a can can generate a repair bill.
If the oil they showed you is nice and clean, but with no road grit then you are a victim of a scam.
Try a independent shop for a price.
If you are handy and have a jack and stands change them your self.
It is not hard especially if you buy the loaded strut with the spring already installed so no spring replacement and compressor is required.
If you have someone else do it or you are comfortable with the spring compressors then heavy duty springs for towing are available.
Perhaps you could get a shop to install heavy duty springs on new shock struts.

[Jon in AZ]

I'll second the idea of an independent mechanic. A good one with whom you develop a long-term relationship is the best thing you can do for your vehicles. Mine has helped me avoid more unnecessary repairs than I can count. He's not much cheaper than a dealer when a repair is needed, but I trust him not to waste my money. An added bonus is he knows his customers, their vehicles, and their driving habits, so he can anticipate problems and catch little things early before they become expensive.

[Keweenaw Bob]

Originally Posted by Mike Magee

Probably not, but why do you ask? Surely they are long out of warranty, and shocks are not that expensive. Buy new ones and keep on traveling!

Forester rear struts (doesn't have shocks) are QUITE pricey, but towing a trailer should have little to no effect on longevity.

[Jerry Laskody]

We had a 2008 Forester and we never towed anything with it. We live on a gravel road however. The rear struts were replaced at 130,000 miles and front struts at 160,000 miles. They do wear out with normal use.

[John in Santa Cruz]

heavier loads DO make shocks/struts work harder as they are trying to dampen the motion of more momentum.... and a trailer puts a fair bit of load on the rear end.

also, struts are not just shocks but also handle the lateral forces against the upper part of the suspension, so they are going to be under more serious load when accelerating and braking with the additional weight of the trailer

[FRED SMAILES]

Originally Posted by John in Santa Cruz

, struts are not just shocks but also handle the lateral forces against the upper part of the suspension, so they are going to be under more serious load when accelerating and braking with the additional weight of the trailer

IMO, BINGO!
A shock in a non strut environment will usually outlast a strut shock because of the lateral forces induced on the shaft of the damper.More weight, more force, more wear.

[Little Richie]

Originally Posted by Jon in AZ

I believe we're talking struts here, not simple shocks, so replacement is not trivial.

Even so, struts are normal wear items. Lifespan varies greatly depending on use. The roads you drive, climate, driving habits, and yes, towing can affect strut life. FWIW the rear struts on my '93 Legacy required replacement at 120K miles, and there was no towing.

Even a basic Scamp 13 carries around 200 pounds on the hitch, right at the limit. Add any cargo in the vehicle and you're probably over, at least a little.

Did that cause the failure? Probably not by itself. Could it be one factor among others? Sure. Towing is considered severe use of any vehicle, and you can expect more frequent maintenance on drivetrain and chassis components.

Fix it and move on. Console yourself with this: it's a lot cheaper than a new vehicle!

Payload is often overlooked if not actively ignored. The available payload number on the inside driver door is the starting point. Subtract all the stuff your are carrying in the car and on the roof, including all passengers and any pets; and the weight on the hitch. When researching what vehicle I needed to pull my current rig I called Ford. They were very clear in noting that after 1000 miles of pulling over the payload there will be measurable excessive wear on the springs, shocks, etc. So, if one are over your limit it could account at least in part for the issues. I also researched air bags. They are great at leveling the vehicle which is important. Ford indicated that airbags will not increase the payload limits. It might improve the ride and level the vehicle, but it does not change payload limits.

[k corbin]

Shocks are one of the things that one expects to replace every so many miles. Much like tires, batteries, brakes, some of the bushings in the suspension, alternators, etc. If you have a lot of potholes where you live then they will need replacing sooner rather than later. So you can't put an average figure of miles on how soon you need them, some people carry heavier loads around than others.

I am in Seattle, our transit system buses are very much overweight for the type of paving we have so all the bus routes in town suffer from big potholes. They can be worse than roads out in the country.

[mizterwizard]

Your Outback Is 5-6 years old. That is a little young to need suspension parts but if you have more than average miles that could explain it.

If you tow with your Outback everything on it will wear out a little quicker. Shocks are no exception but they aren't particularly vulnerable. Just count the cost of the shocks as a part of the general cost of having fun, along with gas, space rent, tires and everything else.

What you have is coil-over shocks. They are not exactly shocks and not exactly struts. Shocks are independent and by themselves. Struts not only incorporate the springs but also hold the wheel upright. Struts take side loads that your coil-over shocks don't see. Your coil-overs take vertical loads that ordinary shocks don't experience. Not that it matters much. If they need to go then that is that.

Dampers damp. They don't dampen. A water hose dampens, it doesn't damp. Something that has been dampened is damp but something that has been damped just sits still. It's one of those which witch type of things. Everybody gets it wrong but it still bugs me.

A quality shock by itself without shipping is about $70 on Rock Auto. Add the spring and it is about $80. A pair of coil-over units with shipping will be less than $200. Since springs sag over time, it is a good plan on all fronts to do the complete unit. Unless you have a spring compressor already it will cost you about as much to rent the tool as it would cost you to upgrade to the complete unit. That is not to mention the safety issue related to messing with a compressed spring.

If you get the complete coil-over unit, the job is trivial. You won't find much you can do on a car that is easier than shocks. Jack it up, block it up, remove the tire, remove one bolt at the bottom of the shock, go inside the back and take 2 nuts off the top of the shock and out it comes. Putting it back in is about the same difficulty. If it takes more than an hour it's because you stopped to do something else.

Since you have coil-over shocks, not struts, you won't need an alignment when you are done. They don't have anything to do with wheel alignment.

Higher capacity springs might be a good idea but where are you going to get them? Rock Auto has standard springs for $45 each. Just another reason to spend $10 extra for complete coil-over units.

For $2000 you can buy an air suspension kit to put air bag struts/shocks on all 4 corners but these are usually sold as lowering units. They would have extra weight carrying capacity but I don't think lowering your car 4 inches is a good idea for a tow vehicle.

For about $700 you can get a set of lowering coil-over shocks/struts that are intended to lower your car from 0-3 inches. If you set them up at 0 inches then you would maintain your stock ride height. The way these work is that the shock and strut bodies are threaded. There are large nuts that go on the threads. The springs rest on these nuts. By turning the nuts up on the bodies the spring gets compressed and raises the vehicle.

With only an additional 200-300 pounds it shouldn't take much to level the vehicle back out. When you don't plan on towing for a while you could back the nuts off and be back to normal. Typically these lowering kits have stiffer springs to compensate for the reduced travel left when you lower a vehicle so they might be just right for your towing situation. With enough looking you might find a kit for just the rear and that might actually be reasonably priced.

This kit even comes with adjustable shocks so when you are towing you could increase the damping but when you are running light you could back it off.

https://www.carid.com/godspeed-proje...25&url=6692831

[steve dunham]

At this point you have two options IMHO ,replace the struts or but an upgraded tow vehicle . In either case you will pay the bill and take the risks
I also have towed ( boat) with a small vehicle and experienced rear strut failure
I figure you end up paying either way , less mpg’s or higher repairs costs .