Rear shock absorbers wearing out unusually fast

General discussion about our beloved Tercel 4WD cars
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Toyotise
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My tercel:: 1983 4WD DLX. 1986 4WD SR5
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Rear shock absorbers wearing out unusually fast

Post by Toyotise »

The dear Tercel is burning through rear shock absorbers faster than we can drive down the rough washboarded dirt roads. First Set of made in Mexico KYB’s were shot after 2000 miles. The latest set of NAPA made in USA only made it 800 miles. With new shock absorbers we get some time of good comfortable driving then it slowly starts to give big rattles and clanks going over bumps, and/or the rear axle starts to bounce and rattle up and down rapidly when braking.

We’re doing everything we can on our end to mitigate excessive wear (driving reasonably on said rough roads 15-25 mph). I’m wondering if maybe we have weak springs? And they’re allowing too much travel which is wearing out the shock absorbers prematurely? The car has 265,000 miles on it and it’s been driven for its intended purpose on unimproved roads for a good percentage of its life. The bushings in the rear suspension are all there, they are not in excellent shape but they’ve got some life yet.

I think I may need some fresher rear springs.
Does this sound like an accurate diagnosis?
Should I stick with stock springs or upgrade to something heavier? (Cut down Corolla springs?, Pathfinder springs?)
Considering going with some heavier duty air shocks?
Maybe some urethane bushings (panhard rod) would help?

What do you all think?
Any similar experiences? Any solutions?
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NWMO
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Re: Rear shock absorbers wearing out unusually fast

Post by NWMO »

I would guess your rear springs are allowing to much motion. I’m running the Pathfinder springs for lift and have a longer mono-shock. I think I have about 50k miles on the set up and I still like how it rides (more truck like).
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drafting3d
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My tercel:: 1985 SR5 100% original

Re: Rear shock absorbers wearing out unusually fast

Post by drafting3d »

https://www.ebay.com.au/itm/13248896214 ... ctupt=true
I was going to get these but started fiddling with weber (and now searching for 3.5 psi fuel pressure regulator)
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NWMO
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Re: Rear shock absorbers wearing out unusually fast

Post by NWMO »

There are cheaper options for the front, look at Moog 81043.
Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

In remembrance of my friend ARCHINSTL:

T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"

"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain
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Toyotise
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My tercel:: 1983 4WD DLX. 1986 4WD SR5
Location: Arizona

Re: Rear shock absorbers wearing out unusually fast

Post by Toyotise »

Thank you for the feedback everyone. I’ll have to look into all the options as far as springs go. I’m not really looking to alter the ride height, but the ones on there for 265k were well used on dirt roads for many years and maybe some tired out.

I got some helpful feedback from the Facebook group as well. Newer stock/ better aftermarket springs were mentioned as well. The general consensus of experience is some adjustable air shocks like Monroe MA700 will help for the rear.
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Toyotise
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My tercel:: 1983 4WD DLX. 1986 4WD SR5
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Re: Rear shock absorbers wearing out unusually fast

Post by Toyotise »

Got around to installing the Ma700 air shocks on the 1986 Blue SR5 this weekend. Running about 25 psi for unloaded stock ride height. Had to redo the carrier bearing while I was at it, all the thrashing on busted shocks did it in (it was starting to sag since I got the car).

Only thing I’m not thrilled with is how the plastic air lines are secured to the shock absorber. Does anyone know of or done a good retrofit ‘hardline’ solution? I ran the thin plastic lines through some vacuum tubing ‘conduit’. That should protect them some. The plastic nuts that squeeze the air line to the o-ring in the shock absorber...well I would like something a little more heavy duty. I dont run the ‘trails’ with our Tercel’s but they do see a fair amount of dirt road usage. Guess I’ll have to run it and see if there are any weak points to improve on. Will keep you all updated.
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My tercel:: 1988 Corolla 4wd Wagon (AKA Corolla All-trac) 5speed, AC, Power Sunroof, Windows, Mirrors, Steering, Locking, Diff Lock, 14" Corolla SX Alloys with Silica Hankook Tyres, 4afe, King Springs, Upgraded Headlights, Full Synth oils, 210,000kms
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Re: Rear shock absorbers wearing out unusually fast

Post by Mattel »

Hi Toyotise. I have had the Ma700s on my Corolla Alltrac (same rear end as the Tercel) for over 30,000 kms and just made sure the valves wouldn't foul anything and loosly zip tied them up and out of the way over the fuel tank and frame rails. I mounted the valve to the tow hitch. how about you?
Previous: 83 Tercel SR5 4wd, 84 Tercel SR5 4wd
88 Corolla 4wd Wagon 5speed, All power options, Fact Sunroof, Diff Lock, 14" SX Alloys, Hankook Tyres, 4afe, King Springs, Upgraded Headlights, Full Synth oils, Tow Bar, 210,000kms
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Petros
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Re: Rear shock absorbers wearing out unusually fast

Post by Petros »

I am not so sure that springs will allow too much motion, the shocks should be dampening the movement of the axle (the "shocks" actually do not absorb the shock, it is a dampener, it job is to dampen the spring oscillation...one of my pet peeves in automotive terminology... they are dampeners- not "shock absorbers"-that has been around since the beginning of car suspensions). the "shocks" dampens independent of the spring rate or stroke, it should be designed to take the full stroke of the suspension as designed by the factory. So I would suspect something else is going on.

a lot of rough road driving on soft springs may allow some regular longer motion than on smoother road driving, but I can not see it reducing the life of a dampener (shock absorber) so much it wears out in about 20 percent or less of its normal life (a reduction in life by 20 percent perhaps, but not an 80 percent reduction). However, that could happen if the springs allow it to sag so much that the shocks are bottoming out, or topping out, too often. that will damage the seals and very quickly result in all the oil blowing out of the shock. if the stock springs are not sagging from stock height, and you are not driving in such a way to always be bottoming the suspension (driving with heavy loads at higher speeds on rough roads), I do not see how the stock springs are the problem. Does your ride height look too low? there is a specification for ride height in the FSM.

Nor the bushings either, unless sloppy bushings are causing a misalignment of the shock mounts, putting a lot of stress on them as they cycle through their motion. This would also be true if there is any bent or distorted suspension parts or mounts, this should be carefully checked out. If so, new springs will not fix it. OTOH, most sloppy bushings will not wear out the shocks too fast, if it was that bad it would be unsafe to drive there would be so much play in the suspension.

Either way, bad springs, bent parts, or sloppy bushings, all need to be corrected so it behaves properly when on or off paved roads. It is difficult to believe the quality of all the available shocks are so poor they give up in less than a year's worth of driving. Factory dampers on most cars, both from the '80s and today, last over 100k miles, even on unpaved roads (mine always have and I drive 3 miles of steep gravel roads every day to get home). If the only ones available to the Tercel4wd are communist made crap, maybe so, but I find it difficult to believe that companies like KYB, Gabriel, and Monroe have allowed their quality to sink that much (even if they have them made off shore).

It is likely we can find a model of performance adjustable shocks to fit our cars. Billstein and Koni (and likely others) always have applications for all kinds of odd and usual cars and trucks, but they are very costly, like $150.-200. each, plus. I just checked Summit racing that sells Koni shocks, and they only show the normal Monroe, KYB and Gabrial shocks to fit the rear of the T4wd, but likely there is something close enough with the Koni, perhaps with some mods to the mounts, that can be made to work well, if you are willing to spend that much. I am told by those that spend that much on their street cars that they can tell the difference. Either that, or they are fooling themselves into justifying spending $600 for custom adjustable racing shocks for street use. personally I think putting those into a show car is just to show off their garage queens at the weekend car shows, since they never actually race their cars.

Perhaps some members on this forum can research what brands and models other off road drivers are using for similar sized AWD cars and small SUVs are using that would not be that costly, and find a good way to rig or adapt them to the rear axles of the T4wd, and share it with us on this forum. there may be some good front strut inserts we can use as well. that would give us an option between the off the shelf $25. KYB-Gabrial-Monoe street shock, and a full custom $1000 racing shock set up.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
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Toyotise
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My tercel:: 1983 4WD DLX. 1986 4WD SR5
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MA700 Air shock test drive

Post by Toyotise »

I got to test out the new Monroe MA700 air shocks today and I’m really happy with them so far. I had about 600 lbs of lumber in the back. Aired them up to about 55psi and the rear was back to stock ride height. No bottoming out over the back country roads and cattle guards. Nicely dampens any oscillations from sudden steering maneuvers.
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Mattel: I routed the air lines directly from the shocks to the interior and installed the air valve right above the rear shock mount. I wanted as few exposed to the outdoor elements point-of-failure possibilities as I could manage. I ran all the thin airlines through a protective plastic tubing. I’ve seen some people install the shocks turned around 180 degrees (so the air valve fitting faces onboard) but you have to cut out a substantial piece of the unibody that strengthens the shock mount. I am unwilling to do that to this car. I would like to fabricate a sheet metal shield to protect the exposed portion of the airline from rocks/ snow-ice accumulation.
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Petros: Everything is in fair order with the rear bushings. Not perfect but not bad enough to merit replacement yet. In all fairness we were running heavy camping loads in the back and driving over very rough washboarded roads and creek crossings. It wasn’t the previous set of gas shocks fault they failed, it was just beyond their design capabilities. Should’ve gone with the air shocks sooner.
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My tercel:: 1988 Corolla 4wd Wagon (AKA Corolla All-trac) 5speed, AC, Power Sunroof, Windows, Mirrors, Steering, Locking, Diff Lock, 14" Corolla SX Alloys with Silica Hankook Tyres, 4afe, King Springs, Upgraded Headlights, Full Synth oils, 210,000kms
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Re: Rear shock absorbers wearing out unusually fast

Post by Mattel »

Great installation job. I've put these on my Corolla Alltrac and they face inboard without touching anything. The 'T' peice seems frail but has stayed well. Ive got ford falcon springs on the back of mine which give a very harsh ride. I hope your valve will not be to esposed there. I was thinking of attaching mine permanatly to an old air compressor in the side panel but don't really need to alter the pressure too much.
Previous: 83 Tercel SR5 4wd, 84 Tercel SR5 4wd
88 Corolla 4wd Wagon 5speed, All power options, Fact Sunroof, Diff Lock, 14" SX Alloys, Hankook Tyres, 4afe, King Springs, Upgraded Headlights, Full Synth oils, Tow Bar, 210,000kms
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