92 awd and 96 awd has the shakes bad when braking

[Tjsprevia]

Hi my name is TJ ,I live on the north coast of Oregon and have been wanting an Egg for some time now .. And there pretty easy to come by out here
Im a fly fishing guide in Alaska and Oregon and tinker with pinball machines and carpentry as well as beating my knuckles with wrenches form time to time ..

great forum.. ! After reading a bunch , maybe it should be called Tims previa page:)

I've got my 92 awd , when breaking , mostly down bigger hills , she shakes real bad , in the steering wheel and peddle ,I've checked the calipers , and had the rotors checked.. Those are perfect ..

if I gas it with my foot on the break peddle , it's smooth .. I checked bearings , and all bushings I can see ..

Rear drums? My 96 is doing the same thing now , just not as bad ..

maybe be I need to get the drums in the Bach checked out ?

thanks for any suggestions!

[TheMAN]

wheel balance or warped rotors
warped rotors can occur at any time if the lug nuts are not torqued down evenly... which is what happens when shops just blast wheels on with an impact wrench without torque sticks or doing the final tightening with a torque wrench

[Tjsprevia]

wheel balance or warped rotors
warped rotors can occur at any time if the lug nuts are not torqued down evenly... which is what happens when shops just blast wheels on with an impact wrench without torque sticks or doing the final tightening with a torque wrench

i had the rotors tested and they are fine.. I took the wheels and rotors off, I never torqed the wheels but installed in a cross tightened pattern..

could it be the tear rotors ? That seems weird, the bearings are also good / and the cv's also appear good ..

thanks tj

[pdgizwiz]

Could be you've got a control arm bushing that's gone soft. Or a spot on the disk that's glazed. Or a combination which sets up an oscillation. I had that situation on my wife's Avalon until I had the bushing replaced.
You could try replacing the pads with OEM parts and lightly sanding the disks to provide a fresh surface. The control arm bushing theory is tougher to confirm, and less likely.

[timsrv]

IMO, the only thing it could be is warped rotors. The Previa rotors are very vulnerable to uneven and/or over tightening. I wouldn't even mess with turning the old ones (new aftermarket rotors are cheap). I would replace and then use a torque wrench when installing front wheels. Snug all the lugs evenly before applying final torque. Tim

[pdgizwiz]

I agree that rotors are the most likely culprit, and that it makes more sense to just replace them than to fuss over more esoteric causes. Turning them might even cost more. I revived a pair once with a D/A sander, but I had more time than money then and they just had a rusty spot from being out of use for a while.

[tomkei]

I agree it's rotors. I own a 1993 2wd and, a 1991 LE. The 93 is an Ohio vehicle, The 91 is from CA no rust. The 93 rotors are Toyota OEM and measures outer thickness within tolerance, but the corrosion on the inside cooling area is so bad the disc sides are so thin. The rear rotors warped, and then fronts followed. Don't recall your location, if the vehicle is driven in a salt and other corrosive chemicals this can occur. The 91 from CA has the original OEM rotors, the wall thickness has not been effected. Just wanted to bring up the rust problem in general.
Hope info helps.

[Tjsprevia]

IMO, the only thing it could be is warped rotors. The Previa rotors are very vulnerable to uneven and/or over tightening. I wouldn't even mess with turning the old ones (new aftermarket rotors are cheap). I would replace and then use a torque wrench when installing front wheels. Snug all the lugs evenly before applying final torque. Tim

hay, thanks everyone for the replies...you guys are awesome, I'm going to change the rotors in the front, they are cheap! Awds are such a pia to work on as you have to lift the whole rig up to spin a tire.. New to me!

Man an the drivers side rotor looked new , I had it tested at o'rileys , they said it was perfectly true..
i will check the passenger sides rotor ... 70 bucks for new rotors is 70 bucks.. Could o' Riley's be wrong?

thanks again I'll keep you all posted

tj

[timsrv]

Did you see them put it on the lathe? Spinning and running a gauge or cutter up against it is the only way to know if it's straight & true. If they only checked one, perhaps it's the other one causing all the issue. Tim

PS: I had a tire shop over tighten my front lugs before. I knew it immediately on my way home. I went back and complained and they loosened and retorqued the wheels. It was better than before, but was still there. Since I'm a tech & didn't want to make a big deal of it I took the rotors off and had them turned. This fixed the problem initially, but it came back. I deducted the rotors were bent by overtightening and then corrected by turning, but not stress relieved. After driving and heating with correct torque, they began going back to their original shape, but since I altered by having them turned, this caused the vibration to come back :wall:. I replaced with cheap aftermarket rotors and problem was solved. Due to the vulnerabilities of the Previa rotors, unless there is zero vibrations during braking, I will typically replace front rotors whenever I replace the front pads. I've never purchased expensive rotors. I usually grab them from rockauto during their close-out sales. For a while Tony's auto parts in Vancouver WA was selling these for under $25 each, but I suspect those days are gone. Tim

[TheMAN]

don't buy cheap rotors... they have substandard venting holes and their castings are crap, which means easier to warp

buy premium rotors

I've bought OEM rotors before and they're even better... but they're stupid expensive... the OEM rotors have anti rust and perhaps anti-squeal coatings on them... you can do that yourself but it takes a of time to do that prep work
not to mention, many aftermarket rotors don't come with the 2 8mm bolt holes for pushing a rusted rotor off

[timsrv]

don't buy cheap rotors... they have substandard venting holes and their castings are crap

It's not like they do anything important, Jeez. Seriously though, perhaps I've just been lucky but I go up/down steep hills with mine overloaded pulling a trailer. I just can't see paying top $$$ for something I usually replace every 50k miles anyhow. When I push the brakes the vehicles stops.........what more could you want?

[TheMAN]

gee.. save a few bucks for a safety item... brilliant! :rolleyes:

[pdgizwiz]

Looks like this topic is one where there is a diversity of different experiences and personal preferences. How we drive, how we like to spend our time and money, the climate and conditions we drive in - they're all over the map.

My own perspective on rotors is that there's no point in changing them unless they are worn, scored, rusty or otherwise compromised in a way that effects their function. I will usually replace pads only if the disks are smooth. I don't race or carry heavy loads down mountainsides, so maybe I'm easy on brakes. I don't live in a part of the country where corrosive slop is being sprayed onto my vehicles' undersides.

Rotors seem to be one of those parts that everybody and their dog manufactures, though, so prices range all over the place. I did a little searching to explore this. A Brembo page has a nice part number interchange guide that helped.
My own van has all-wheel disk brakes and ABS. I looked for the front rotors at OEM sources, Rock Auto, Napa, ebay, and Amazon, I find that many ebay sellers are trying to sell their last single rotor. That's not helpful. Many ebay and Amazon sellers don't specify what brand they're selling. That doesn't help either. Rock Auto lists their offereings as either "economy", "Daily Driver", or "High Performance / heavy duty". The "HP/HD" offerings appear to be drilled/slotted, etc., and I didn't bother with them.

Front brake rotor (w/ABS) 271mm OD 25mm thk
Brand_______________ part number ______________price _______source _______________notes
OEM Toyota _________43512-28090 __________ $64.31 ____Toyotapartszone_____ + ? shipping
Pronto _____________BR31106 __________________$16.37 ______Rock Auto Econ _____+ ? shipping
Bendix _____________ PRT1722 _________________$19.35 ______Rock Auto Econ _____ + ? shipping
Wagner ___________BD125237 __________________$35.99 ______Rock Auto DD ______ + ? shipping
Aimco _____________31106 _____________________$40.89 ______Rock Auto DD ______ + ? shipping
Raybestos ____________96218R _________________$21.79 ______Rock Auto DD _______+ ? shipping
Brembo _____________9591610_________________ $69.79 ______Rock Auto DD _______+ ? shipping
Brembo via Altrom ____ 094 2473________________ $26.00 ______Napa _____________ local pickup
Napa Brakes __________NB 4886218 _____________$35.99 _______ Napa ____________local pickup
Raybestos __________96218R __________________ $32.96 _______Amazon__________ free shipping

It looks like the best bargain here is the $26 Brembo at Napa. I can walk in and pick it up. It's likely the same as the $70 part that Rock Auto has. Although RA has cheaper rotors, they're likely from some dirt-floor foundry in China, whether they have a familiar-sounding name or not. They might all be out of China, of course, and still vary wildly in quality.
With a four-to one spread in cost, there are lots of choices and lots of nebulous factors. I doubt that there is a direct relationship between quality and price. If I needed a pair of these disks and didn't care about the cost difference, I'd probably just go OEM and rest assured that I was getting what the car came with. If I was short of funds and had a family to feed I'd probably take my chances with the $26 Brembos. If I was a sucker for marketing words like "Premium" I might spring for the $36 Napa store brand units.

[timsrv]

Another thing to consider is the Previas have different braking options. The ABS option has dual piston calipers and bigger rotors. Due to this, on these models, Toyota put on 15" wheels (14" rims will not fit over the larger rotors/calipers). Buying the cheap rotors might not be a good idea if you have the smaller rotors and single piston calipers (especially if you're carrying heavy loads down steep hills). Fortunately for me I have ABS w/4 wheel disc brakes (big rotors w/dual piston calipers). In my case the brakes work awesome and aside from an occasional warped rotor, I've never had issue with the brakes. Of course I am cautious when going down steep grades. I down shift and I don't ride the brakes. It's been my experience the expensive Toyota rotors warp just as easily as the cheap aftermarket Chinese ones (ymmv). Tim

PS: They don't salt the roads here, so we don't have those kind of corrosion issues. Perhaps if we had this issue I'd consider spending more $$$ on rotors.

[Tjsprevia]

Well I just finished putting new , inexpensive (35/unit) rotors on both vans, like I said, I had the rotors tested on the 92 ( not on The vehicle).. They tested good..

replace them hem anyway thanks to the advice on this forum , no more shake , just smooth breaking power !

Now both the 96 and the 92 are smooth breaking ...

thanks to all who replied ....

[TheMAN]

good to hear
make sure you use a torque wrench on those lug nuts.... never blast them on if you don't have torque sticks!
torque them to 80ft lbs... that's good enough... if you're "worried", I wouldn't go past 100ft lbs