Prado suspension ball joint failures @ ExplorOz

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Prado suspension ball joint failures

Submitted: Monday, Sep 02, 2002 at 00:00

Rory Thompson

I have a '96 Prado ex japan and was driving when the front right suspension unit "fell off".
Itlooks as if the upper ball joint popped out and allowed the lower ball joint to be moved to an excessive angle and then also pop out.
Result is the whole wheel suspension unit and drive shaft under the car and held only by the streering arm and brake hose.
Frightening at 30 kph, let alone at higher speed.
Replace upper and lower ball joints on RHS and upper on LHS.
Wanted to replace the LHS lower ball joint but Toyota had a freeze on releasing any parts from stock.......WHY??????

Mine is not the only one.....
I have seen two Surf KZN-185's (same front suspension as Prado) that have had ball joint failures.
First 6 months prior was same situation as mine but LHS and at 80 to 90 kph......just fell off.... much more damage.
Second was after mine...steering wouldn't return to centre without a nudge from the wheel...checked ball joints and found one about to pop out.

Pleas contact me if you have had a similar failure....ball joint designs are not fail-safe and should be redesigned.
J. Rory Thompson
MIEAust. CPEng. membership no. 2180308

AnswerID: 6270 Submitted: Monday, Sep 02, 2002 at 00:00

JohnF replied:

Well, well, well, finally someone else with the same problem I had. I posted on this site twice, on 16 Aug 2001, and 10 Aug 2001.
Search on my name, and you should get the story.
I wrote to Toyota in May last year, and got the right royal brush off.
Then lo and behold they sent me a letter on 30th July (general letter to all Prado owners), which in my opinion makes an admission they knew of the problem. I wrote back telling them so, and making some noise of pursuing them legally. Well, their 30 days are up, and I'm seeing my lawyer this week.
Those front ball joints caused me some considerable grief and expense, and as i said to them in my letter, the matter wouldn't go any further if they had sent me an apology.

Reply 2 of 4

FollowupID: 2779 Submitted: Tuesday, Sep 03, 2002 at 00:00

Rory Thompson posted:

John F, it was obvious to me after my experience that thebdesign of the front suspension is suspect.
1. the "rolled over" trapping of the lower ball joint carries the full corner weigth to the lower wishbone then the spring -shocker.
Rollover production operation is not so easy to maintain optimum and thus strength will vary, despite Toyota Total Quality Control and Process statistical Controls.

A safer design would use a two piece housing with a machined lower portion bolted to a revised machined upper section thus trapping the ball and with thicker metal at the base to give a longer wear life.

Also, the press fit of the upper ball joint does not allow replacement in the bush. You need a 5 tonne press!!

The suspension member needs redesign to chage the upper ball joint to a bolt on design that is readily replaced by any maechanic using spanners and at most a ball-joint wedge.

PS I worked in the automotive componets industry as a designer production engineer amd manager for 27 years. We supplied all Toyota steering columns, suspension links and brake drums and discs.
Toyota are usually very conservative designers. Not so here.

My failure and one of two Surf KZN-1185 failures I have seen WERE NOT DUE TO SEAL FAILURE AND LOSS OF LUBRICATION.... THESE TWO WERE JUST DIRECT DISLOCATIONS OF THE BALL JOINTS.
Rubber seals were intact and joints were fully greased.
My car did have a front impact prior to my purchase that may have stressed the lower joint but this could not be detected and the joint had no looseness, the Surf-185 had no prior damage.
IF you need support in your case I can assist.
Regards, J. Rory Thompson
MIEAust. CPEng. 2180308
B.Tech. Mech. A (University of Adelaide 1967)
M. Eng. Sc's. Materials Welding & Joining (U of A 1999)
I am a Chartered Professional Engineer, consult in the auto industry and design and build sports cars.

FollowUp 1 of 2

FollowupID: 2782 Submitted: Tuesday, Sep 03, 2002 at 00:00