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9Th Gen. Corolla Rear Suspension Help?

By Hamilton Felix September 9, 2014


  • 23 posts

I have a 2007 Corolla 5-speed. My wife and I are not small, and our two boys are definitely adult weight. We use the car quite a bit for shopping, and sometimes we even pull a small trailer. Frankly, given our "prepper" tendency to carry emergency gear (how many commuters carry axe, shovel AND a chainsaw in winter?), there's always some weight in the trunk.

I'm probably out of luck (definitely striking out so far) finding much suspension help for a strut suspended car, but thought I'd ask. It was easy to put air lift bags inside the coils of my Crown Vic, and I even carry a small compressor. But I don't know of an easy way to increase the load capacity of car with strut suspension. I just want to keep the rear from sagging under full passenger and trunk load.

I'm also thinking of using the Corolla to pull my old Jayco pop-up camp trailer. The Corolla is rated to tow 1500 lbs. and the Jayco weighs less than that.

I vaguely remember little odd shaped rubber "wedges" that people put between the turns of coil springs back in The Day, but I can't see that as a good alternative.

It used to be helper leaves for leaf springs, air bags for coils, or air shocks as a last resort (shock mounts are not usually designed to carry weight). But with the coil-over strut, I don't see an answer, short of custom struts with higher rate springs (and we're NOT considering any of the "performance" lowering springs out there).

Any thoughts?

Those coil spring "wedges" are still out there, but can make the ride either pretty punishing or worse, affect handling in negative way.

Custom springs are an option - but don't discount a quality aftermarket performance spring. I'm running TRD springs, which drop the ride height about an 1" all around, but the spring rate is significantly higher than stock without being punishing. They are progressively wound, so the first bit of travel is pretty soft, rides like stock with standard load - but once loaded down, it really helps keep the strut from bottoming out.

I found that I could pull a little 4x8 mini-trailer with ease with the lowering springs compared to the OEM ones. Even though I'm dropped an inch from the start, the performance springs still end up riding "higher" then the OEM ones did with the little trailer.

surprising how many corollas are doing towing..I'm going to look for a light boat next year to tow with my corolla..

are the factory springs not progressive spring..ie more or exponentially increased resistance with the linear compression ??

I'm not sure on the rear springs on the 9th gen - I think I read that they are linear, given the beam type setup they have. But they are definitely tuned to the softer side - just increasing the spring rate just a bit will make a huge difference in loaded performance.

  • 23 posts

Sorry to be so late getting back and reading this - too much happening at home. So TRD springs start out an inch lower, but actually ride higher with a full load? Makes me wonder about spring rates, TRD vs stock. Also makes me wonder how much more damping is required. Usually a heavier spring needs a stiffer shock.

The Monroe Quick Struts I put on the rear of my 2005, are still riding higher than stock and seem really stiff after 2600 miles.

I have noticed that the headlights are aimed too low and need to be adjusted. New KYB in the front .

The TRD are progressively wound - so initially, they act like a slightly stiffer OEM spring - struts don't seem to be bother too much about it. I'm running TRD springs on OEM replacement KYB struts - have probably 140K miles on them - which for this sort of setup is astounding. Struts are definitely worn out at this point - damping is not as good as when they were new, so they will be replaced with KYB again.

Spring rates - I don't remember off hand - I think the TRD are 25%-100% stiffer than OEM, depending on compression. I think the rear OEM spring rates are around 100lbs per inch? Most aftermarket is atleast 50% higher than that - so just replacing the springs would buy you some extra load capacity. As long as the spring rate isn't excessively different than the OEM ones and they aren't much shorter than stock to make sure they have a full stroke of the strut - should be safe to use OEM like struts, no need for special lowering struts or adjustable damping ones - unless you want them.

Good know - thanks for posting that dom! Pretty sure OEM is 100 lbs/in to 125 lbs/in on the Corolla, but I haven't found a reliable source for that spec.

As it turns out, my stock rear coil springs measure 11mm (0.43307") in bar diameter... Moog and Raybestos (and likely Monroe quick strut) rear coil springs are 11.684~11.938mm (0.46~0.47") in bar diameter. So they could be considered as 'cargo springs' compared to original.

Thanks for that information dom. Someone just gave me a set of calipers so next time I get a chance I'll measure my springs.

I already carry a shovel in the winter but now I have to buy a chainsaw and an axe so I won't have to adjust my headlights.

  • 23 posts

Good Plan. I normally carry axe, shovel and a few other tools. But in winter I add a chainsaw, tire chains, cold weather gear and a few extra things. Guess I need to dig out the calipers and start looking at springs. I really appreciate all the spring info.

  • 23 posts

I'm googling around a bit, reading very mixed reviews on Monroe Quick Struts, even seeing a comment to the effect that neither KYB (I used to say that stood for "Keep Your Bilsteins" when I was a snobbish Saab 99 Turbo owner) nor Monroe measure up to OEM. I do recall having KYB struts put onto former wife's 2003 Malibu, and they were pretty good.

True confession: I bought the car with 46K in May 2008, and it currently has over 260K on it. Very recently, we had clutch replaced (my wife learned to drive stick on this car) and front brakes rebuilt. Other than that, it's pretty much just buy gas, oil, filters, wiper blades and tires. Even at this mileage, I'm not complaining about ride or handling, I just want a bit more rear load capacity.

Hey, I just had a memory flashback to when a friend's 64 Impala was sagging under the load of big toolbox in trunk and small travel trailer behind. I swapped in springs from a wrecked 63 Impala Station Wagon we had on the place, and suddenly Bob's Impala looked like it was street jacked. The trunk load and the trailer were just enough to make it ride level. I just realized the Matrix is the modern Corolla Wagon. Does anyone know if the Matrix has rear struts that are physically the same except for higher spring rate?

I still have not measured my springs . But I wonder if some of the bad reviews for Quick struts are because of overly stiff springs.

And yes it's always good to be prepared.

OEM struts are KYB... My Monroe struts are the most durable and they work remarkably well in our extreme rugged roads under demanding driving conditions.

Matrix FWD rear coil springs are about the same, but AWD rears would be overkill at over twice the spring rate and over 50% more design load compared to aftermarket which already offer more support than OEM.

http://www.rockauto.com/catalog/x,carcode,1432901,parttype,7512

Monroe has the same rear quick struts with the same part number for either Corolla or Matrix FWD.

  • 23 posts

Interesting... Sure sounds like FWD Matrix is a Corolla wearing different skin. That doubled rear spring rate makes me wonder if 4WD Matrix is a substantially different animal, the way Pugeot wagons used to be much different and heavier duty than sedans.

A number of the Quick Strut negative reviews complained about rattles and noise. I think there's a nut that should be checked for torque before installation. Also, I read a complaint about wrong number of holes and screw holes not lining up. But I don't recall now if that was a Corolla review or another Quick Strut tale that Google found.

  • 23 posts

I have done shocks over the years, and a few coil or leaf springs. How difficult is a rear strut job for a home shop?

It's easy enough. I replace my own struts and reuse the coil springs. You can also replace the strut along with the coil spring instead of getting a complete strut, spring and mount assembly. You just need a spring compressor set.

http://www.ebay.com/itm/14-Coil-Strut-Spring-Compressor-Remover-Installer-Auto-Tool-Cars-Trucks-/271501059893?hash=item3f36b96735&item=271501059893&pt=Motors_Automotive_Tools&vxp=mtr

2004 Corolla repair manual- Rear suspension: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=7&ved=0CEUQFjAG&url=http%3A%2F%2Fau.toyotaownersclub.com%2Fforums%2Findex.php%3Fapp%3Dcore%26module%3Dattach%26section%3Dattach%26attach_id%3D20688&ei=bG1OVObSGMz5yQSM54HYDQ&usg=AFQjCNGYgzfLbbIoP_URw0UorCcqSDJ-7Q&sig2=Nx0L2VdzN4TYl86j0VaNqA&bvm=bv.77880786,d.aWw

Hamilton Felix Just wondering how much I should expect to pay for clutch replacement ,mine is now slipping in 3rd 4th and 5th gear at 225,000.



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