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Active UZZ32 Valve Body Reseal

October 2003

by Peter Scott

I resealed my UZZ32 Active Valve body hoping to eliminate a high speed right hand corner bounce - no luck. BUT the reseal did do two things:

  1. No more sag when car is parked
  2. Car smoothly adjusts height when at stop lights - no more sudden suspension movements.

So these two things alone made it worthwhile for me. Stay tuned for front shock rebuild and further sensor swaps. Disconnecting boot sensor removes bounce and makes car softer - but error message is displayed.

Bounce theories (not proofs!):

A. The valve body (front passenger fender) needs reseal. Seals leak letting pressure out of shock, shock pumps itself up again, leaks out, pumps up etc etc. There is a seal kit listed for $70 in parts CD - I have this kit and will attempt open heart surgery on Active this weekend. Kit consists of 20 or so o-rings - funny sizes etc - Toyota Japan agreed to manufacture this kit for me - took about 8 weeks. (NO THIS DIDN'T FIX IT)

B. Bottom part of shock - the sealed pressure part is stuffed. Don't know how it works - but new ones are available for 400 or 700 bucks - forget which. A seal kit for 120 for top half and a new bottom half gives new shock that isn't that expensive. BUT what does the bottom sealed part of the shock do? and how do you know if it's stuffed and what would it affect?

c. Nitrogen accumulator is stuffed. No idea what this is or what it means. I can guess, but I don't KNOW.

My car has a bounce only through left hand bends with very high g-force. It is not speed related - only g-force sets it off. Only notice it on racetrack or driving with Rob Hayden (same thing really!). Right hand bends it is perfect. A real pain at Mallala and Phillip Island - my exhaust has bounced off!

My bounce is affected by grip of surface and tyres. Race tyres on dry track give maximum violent bounce. Kumho's 265's street tyres on damp road no bounce. Others have also reported tyres affect on bounce. Pirelli PZero comp 235/45/17 inch tyres didn't bounce like my 225/50/16 540s semi slick tyres.

Bleeding didn't affect my bounce. Only Rob and racetrack guys will ever feel my bounce - it doesn't exist during normal or spirited street driving - only "racing".

So grip levels and g-force affect my bounce the most. The car has always had this. Nothing I have done has affected the bounce. At Mallala I had to change driving style, slow in and spin tyres out to stop bounce - I couldn't corner at maximum g's for fear of bounce.

At Phillip Island corner onto main straight is a lefty - perfect - but right hander at 200 kph at end of straight is uncomfortable and honda corner is violent. - rest of track is ok. MG right is ok.

So there you go.

If anyone knows or has any theories I'd like to hear them.

Like what does the sealed bottom part of the Active shock do?
Pics of exploded shock are here:

Could it be some g-force sensor stuffing up?
Why only right hand bends?
Why do some Actives have slow speed, speed hump bounces (not mine)?
What lets pressure out of shock?
Is it some feedback loop?
Could it be electrical (sensor?) or hydraulic seal?

Rebuilding top half of shock didn't fix it.
Bleeding it didn't fix it.


The text said to tighten allen screws top of each strut to lock suspension - stop it collapsing when you removed the lines from the valve body.
Also several warnings about only working on valve body in clean room.
No fiber gloves.
NO rags.
Bare hands or clean rubber gloves with no powder.
No compressed air.
Natural air dry only.

Had to bag up and wire tie all the lines as they were undone. Made a special service tool out of some bookcase mounts. Need to make another one to remove the filter somehow.
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Valve body is spotless inside. BUT the old o-rings I am replacing are squared off - you can see it with the naked eye - they are worn for sure.
So there's hope that the Toyota Valve Body Overhaul Kit will do the trick.

The filter is stainless steel mesh - washable - never need to buy another - explains it's $350 price tag a bit. The filter did have some crud in it - looked like little bits of metal - clean shiny aluminium- not much - the rest was spotless.
I didn't use the seal for the pressure sensor off the side of the filter -looks like it just sends warnings if pressure gets too low. - or the four little o-rings for the other mystery bits.
It just didn't seem important on inspection.

I rang James at Castle Hill toyota and asked for the overhaul kit for the UZZ32 valve body and he did the rest. It's an offical Toyota Kit.

I'll send the old seals to Neil - see if he can match them up. Email me your postal address Neil at

I don't have enough fluid for today - three more cans arrive tomorrow - they were on the computer but not on the shelf on Friday!

Changing the seals was easy, bumper removal was easy, removing the valve body was ok. The holding bracket was easy.
Keeping everything clean is a pain.
Figuring out what to do, wondering what everything is for, that's the tough bit - it's coming together though.
It doesn't seem so hard at all now that it's nearly done. I was dreading it. Same as shock rebuild.
I just hope it starts, bleeds, runs and works now.
It's open heart surgery on an Active.
Special tools were replaced with bookshelf brackets to hold body on vice. The filter removal tool was just two screwdrives and a spanner - it's not that tight and o-ring seals it.

So I'll put it back in today, fill it with my 1 can of fluid. - Finish it tomorrow. I have lots of photos.
Then I need to make the 4 point harness brackets, put the extingusiher back in, pretty up the racing wheels and I'm ready.

I was thinking of swapping over those electric solenoid things left to right to see if they were the problem - but the wiring is fixed length and they won't swap.

So although it wasn't a hard job - there looks to be plenty that can go wrong, some high risk stuff. And it's not even going yet and who know's if the problem will be fixed. Know tomorrow night if the the fresh blood arrives.

And it doesn't take long for the clear fluid to go green - my old can the fluid drips around the top have gone green. And the fluid in the system has start to go green as well. It doesn't stay clear for long at all.

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old and new o-rings - top one has squared off.

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One of the 5 valves

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stainless filter before cleaning.

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Bumper has to come off for sure.

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plastic bags and wire ties for every line.

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Taking the bumper off and removing the valve body I would have been lost without the workshop manual in English and Japanese. You will need a copy for sure - the workshop manual is the best thing to have for your Soarer. Even if you don't work on the car yourself you can print out the pages and hand them to your mechanic.
I wouldn't attempt this without the manual.

The impression I got from Toyota Japan was that no-one had ever asked for a seal kit before ever. They agreed to manufacture one for me - estimated 10 days stretched to nearly 2 months. But I don't know for sure what the situation is.
Sometimes I get the impression that because of depreciation in Japan and high cost of repairs, the 32 didn't get fixed much. Then once exported no-one knows how or what to do so they still don't get fixed much. Hence I lot of 32's limping around wounded - which is a real shame.
It would be great to talk to a Japanese Toyota Mechanic who has that official "Toyota UZZ32 Service Technician" certificate on the wall and ask what does cause bounce, what are common problems and fixes etc - but what are the chances of that? Do Toyota Japan still service and repair UZZ32's?
I don't know.

No change. The car drives the same as before I reckon. The high speed right hand corner bounce is exactly the same. Normal ride I didn't really pay attention.
So on my car resealing the valve body made no difference to high speed bounce around right hand corners. Left hand corners are still a dream.

Part number for seal kit is
List price $85, Net $59.09, GST 6.53, freight 6.20 total of $71.80.
Castle Hill Toyota 02 9680 2233

I dont think it's the YAW sensor.
The yaw velocity sensor is a tuning fork vibration type autogyro, which measures the turning angular velocity of the vehicle by detecting the Corioli's force generated in a transducer.
It's for the 4WS.

So next for me is to reseal the front shocks.
Test again.
It might be Lateral G Sensor, maybe one of the 3 Vertical G sensors or the Logitudinal G sensor - but I don't think so - It seems to be a Lateral G thing in my car. I don't know if it is similar to the low speed bounce some get over speed humps.

At least with the sensors we can change them car to car to see if problem follows sensor.

So after the front shocks and sensor change - I'll have a look at lower part of the shock if still not fixed.

We'll get there.

Bounce now eliminated!
I disconnected the two acceleration sensors in the boot.
Got Warning BING straight away.
Drove anyway.
Car softer - steered different too.
Still kept pretty level - still drove ok - different feel - not so harsh.
So off to the test track.
NO bounce.
Drove harder.
No bounce
Drove real real hard - still no bounce.

Reconnected sensors to other side, but on inside of pillar - so stickers still face backwards.
Bounce same as before - still get it right hand corners.
Swapped sensors so they are on opposite sides but facing wrong way.
Bounce same as before.

Unbolted sensors, bounce gone.

Put sensors back on, left them hanging upside down. Car went spastic - only just completed a U-turn. Car hopping, undulating at walking pace - thought it might blow up - car went nuts. Didn't like that at all.

Unbolted sensors - no bounce - but car has different feel for sure.

So something going on here for sure.

I will try to swap sensors with different Active - see what difference it makes.

If you have an Active with bounce problems, unplug the sensors and let me know what happens. Car is not damaged. Plugging sensors back in car returns to normal and warning goes away. It must default to a limp home suspension mode which isn't too bad.

I am so surprised how much these two sensors affect the suspension.

There are two of them in the boot - one each side. Red sticker passenger side, blue sticker drivers side. Take of side boot carpet - behind metal column you will see them - two bolts hold them on - but just press tab with fingernail and pull plug and see if bounce goes away.

It might just be a faulty g sensor giving us so much grief!!!!

Here's a pic of the passenger side sensor:

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I would have thought that swapping sensors would move problem to other side - but I couldn't make that happen.
Not sure what is really going on yet.

Simple three pin plug on each sensor.


Might be a group buy of new sensors coming up - we shall see.

I guess my concern is that it is not the sensors at all. But removing them puts suspension into limp home mode and it then ignores everything. So it might be the central G sensor or the g sensor computer or some other thing. I'll only really now after swapping the sensors with another Active that doesn't have the high speed right hand bounce problem.
If it still has the same problem then it's more swapping and more troubleshooting. Might be time to give Richard Ashcroft a ring! :)

It's not the boot sensors. Went for a fang in Richards car and it is fabulous. Took boot sensors out and put them in my car. Bounce is the same.
So it's something else.
So we can cross the following off the list for causing bounce.
Rebuilding rear shocks with a seal kit.
Bleeding system
Rebuilding valve body.
Rear boot acceleration sensors.

So when the computer goes into limp home mode with boot sensors disconnected the suspension doesn't bounce, but car is softer. It may well be one of the other two acceleration sensors. No time to check them today. But we will replace one at a time until bounce is fixed or they are also crossed off the list.

I reckon it is the lateral g sensor under the ashtray. hmmmmm.

I don't think disconnecting sensors will harm car. The car loses it's hard edge that's for sure. Still drives ok - handling is still ok. I'm going to race it tomorrow with no sensors. I think the race tyres will give it a good workout. I'll replace the other two sensors next week perhaps - it still might be front shocks needing a reseal.
It's interesting that the limp home error mode gets rid of bounce.



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