Anyone know the torque quoted by Toyota for the front Strut-to-hub carrier bolts/nuts?

[olddriver]

Car 1.3 Corolla December 1998

 

Socket size is 19 mm and bolt appears to be 12 mm, see:-

 

http://www.metricmcc.com/catalog/Ch1/1-2.pdf

 

The Haynes manual states the torque is 274 NM or 202 lbf ft, which seems quite high.

 

Page 62 of an old "Britool mechanics tools" "Tightening torques" states that the highest torque for a 12 mm bolt is for a "14:9 Quality" (I have no idea what that means and neither does G00GLE) fine thread bolt, and is 219 Nm.

 

History:-

 

My local garage fitted the front shockers, and said the tracking was just outside tolerance. The front tyres initially squealed slightly on roundabouts but that disappeared after a few weeks, so I wondered if something had moved. At 2,500 miles later, I torqued the 6 off "Strut upper mounting bolts" to 39 Nm or 29 lbf ft, (as given in the Haynes manual), 5 did not appear to turn but the 6th turned about 1/8 of a turn.  Consequently, I am concerned that the front "Strut-to-hub carrier bolts/nuts" are not torqued correctly.  My torque wrench only goes up to 135 NM or 100 lbf ft, and I applied that torque to the "Strut-to-hub carrier bolts/nuts" and none of the bolts appeared to turn. 

 

Can anyone please confirm the figure quoted by Toyota?

 

My local tool hire does not have a suitable torque wrench, can anyone please advise if I should just let it be and occasionally check the 135 NM or 100 lbf ft torque on the bolts?   

 

Note:  At the time of fitting the shockers, the front tyres were near to replacing, so I waited until they needed replacing before checking the torque, and fitting new tyres, when I saw that the tyres were unevenly worn and had the tracking corrected.

[oldcodger]

Hi,

Cannot give any specific info, but looking at my manuals  the later Corollas  are about half the force of yours.

Looked in my old Mk1 Avensis book and that also has a very high figure of 255nm, so your setting  is not alone.

From general info, I read that those bolts are special high strength and sometimes one can have a higher rating than the other; there is a number stamped on the bolt head.

They also control the camber setting so if tightening, the bolt must be kept still and  only the nut moved.

There are quiet a few torque wrenches around going up to 300nm, here just one I came to first.

http://www.toolstop.co.uk/norbar-13445-torque-wrench-adjustable-ratchet-push-through-1-2-in-square-60-300-n-p69674

[TomdeGuerre]

6 hours ago, olddriver said:

Car 1.3 Corolla December 1998

 

Page 62 of an old "Britool mechanics tools" "Tightening torques" states that the highest torque for a 12 mm bolt is for a "14:9 Quality" (I have no idea what that means and neither does G00GLE) fine thread bolt, and is 219 Nm..

The 14,9 Quality is a reference to the Property Class of the steel ie it’s a numerical code made up of two numbers separated by a dot (or nowadays a comma). The number to the left gets multiplied by 100 to give you the ultimate strength in Mega Pascals (MPa) while the number to the right when multiplied by 10 times the preceding number gives you the yield strength. 

[TomdeGuerre]

3 hours ago, oldcodger said:

Hi,

Cannot give any specific info, but looking at my manuals  the later Corollas  are about half the force of yours.

Looked in my old Mk1 Avensis book and that also has a very high figure of 255nm, so your setting  is not alone.

From general info, I read that those bolts are special high strength and sometimes one can have a higher rating than the other; there is a number stamped on the bolt head.

They also control the camber setting so if tightening, the bolt must be kept still and  only the nut moved.

There are quiet a few torque wrenches around going up to 300nm, here just one I came to first.

http://www.toolstop.co.uk/norbar-13445-torque-wrench-adjustable-ratchet-push-through-1-2-in-square-60-300-n-p69674

Are they eccentric bolts same as they use in some VW’s to control steering angles?

Seems to me the high torque figure would be to accommodate the friction load of the head of the bolt against the mounting plate. If you tried to apply that kind of torque to the nuts you would almost certainly strip them

[oldcodger]

2 hours ago, TomdeGuerre said:

They also control the camber setting so if tightening, the bolt must be kept still and  only the nut moved.

Are they eccentric bolts same as they use in some VW’s to control steering angles?

Seems to me the high torque figure would be to accommodate the friction load of the head of the bolt against the mounting plate. If you tried to apply that kind of torque to the nuts you would almost certainly strip them

Am only going on what I have read about the 2002 onwards models, these pics might help, though it does not explain why the 1998 model is such a high torque, though as said looking in my mk1 Avensis manual it has the same type of strut mounting and also has a high torque.

I replaced the dampers on my Avensis a long time ago, and cannot be 100% sure, but do not think the bolts were eccentric, though the 98 corolla may be totally different ?

 

[TomdeGuerre]

So it looks like Toyota fits crash bolts from the factory to set the camber. A bit Heath Robinson if you ask me, having clearance holes in the strut and stub axle mounting and then using different diameter bolts to get the camber right and depending on a very high bolt torque to clamp the setting. All this when Toyota, as the OEM, should have got the setting right with proper tooling from the gitgo.

I’m also concerned with what OD said about the new tyres squealing at first on roundabouts, maybe it was to do with the rubber mix of the tyres but it might also have been because the wheel alignment was wrong and the tyres were scrubbing. If this was the case they might have stopped squealing now because the new tyres have become worn - either on the inside or outside edge(s) – and the wear will become more apparent as the mileage increases.
 

[olddriver]

Thank guys.  However, my Haynes manual for Corolla July 1997 to Feb 2002, section 10.2, does not mention anything about camber when refitting the "Strut-to-hub carrier bolts/nuts".  Additionally, at the end of the suspension section, 10.23, it states that "only the toe-in is adjustable". 

[olddriver]

40 minutes ago, TomdeGuerre said:

I’m also concerned with what OD said about the new tyres squealing at first on roundabouts, maybe it was to do with the rubber mix of the tyres but it might also have been because the wheel alignment was wrong and the tyres were scrubbing. If this was the case they might have stopped squealing now because the new tyres have become worn - either on the inside or outside edge(s) – and the wear will become more apparent as the mileage increases.
 

Perhaps you misread my post.  The old tyres, probably only the offside front, "initially squealed slightly on roundabouts but that disappeared after a few weeks". After 2500 miles I had new tyres fitted AND the tracking checked and adjusted, these new tyres have not squealed.