Sax Suspension

Submitted: Wednesday, Jul 03, 2013 at 11:38
ThreadID: 103076 Views:6303 Replies:3 FollowUps:7
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G'day all,
I have recently had Sax Suspension upgrade installed in my 2012 Mazda BT50.
This was done by CVSS in Underwood in Qld. The service was performed at a reasonable price and they were very accommodating so I couldn't fault that part of the job.
The problem is that now I get a significant vibration when accelerating away from a stop or after slowing down below say 100KPH.
I have had a front wheel alignment done post the upgrade (as recommended).

Has anyone experienced similar situations?


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Reply By: Thinkin - Wednesday, Jul 03, 2013 at 13:39

Wednesday, Jul 03, 2013 at 13:39
Hi Shakeejob,

Which kit did you get, 3sds,the equqlizer lift kit, or hd leaf spring?

Has the rear axle pinion angle alingement in realation to the front uni-joint been changed? This may put a vibration through the tailshaft if changed too much.
AnswerID: 514206

Follow Up By: Member -Shakeejob - Wednesday, Jul 03, 2013 at 17:52

Wednesday, Jul 03, 2013 at 17:52
G'day Alpero,
I got the 3sds. this lifted the chassis 70mm but I was led to understand that they install bushes to conteract any problems that arise.

They have offered to get Driveline systems to have a look at it so hopefully it will get fixed

FollowupID: 793134

Reply By: Ross M - Wednesday, Jul 03, 2013 at 19:45

Wednesday, Jul 03, 2013 at 19:45
G'day Shakeejob

After a suspension upgrade/lift there is usually a vibration and/or shudder on take off.
Most after market springs do not allow for the lower pinion position and many also point the pinion downward toward the ground than the previously position.

Mazda BT50/Ranger (when standard) has the diff pinion around 2 to 3 degrees upwards from horizontal and both of the rearmost unis run about 3 degrees of driveline running angle. I have measured these.

After suspension mods the pinion position/angle relative to the centre bearing needs to be altered to correct any effects caused buy the lift.

Also the centre bearing needs to be lowered around 5 to 6mm so it also corrects the driveline angles and makes both the middle and rear unis run close to equal if not the same angles.

Nearly ALL suspension mobs do not address this issue and duck and weave to avoid doing it properly, they should have done it in the first place but they DO NOT.

Often the system is fitted by people who can undo bolts and stuff, but do not understand the dynamics they are altering or how to recognize it and don't seem to have the skills to understand it and correct it.

If yours vibrates on overrun ie. trailing throttle/backing off, I strongly suspect the pinion will be pointing downwards too far and only a corrective wedge in the spring seats will restore it, IF they get them fitted the correct way around that is. Don't laugh it was done recently by a very well known PROFESSIONAL Orstrayan aftermarket maker/supplier based east of Melbourne CBD.Brisbane Branch.

The significant vibration may be the tailshaft speed shudder which is caused by the centre bearing uni operating at too much angle and forcing the centre bearing to flutter in it's rubber mounting. If left to continue IT WILL DESTROY the centre bearing mounting rubber.

Universal joints accelerate and decelerate twice EVERY turn so any angle over the norm or not matching the other in the set will vibe and or cause short uni life.

Fitters seem to be blissfully unaware of the physics behind drivelines and also seem unable to detect vibrations IF road tested despite the owner noticing it immediately they drive it afterwards.
Who ever did the job is incompetent, and as mentioned previously in other posts, "the company should have sold you a solution and not a problem".

This happens so often, likely more times than you have had hot dinners.

If a qualified,trained, competent, warm and vertical mechanic fitted the system he wouldn't have let it go out without being correct.

Cheers and hope this helps.

Ross M
AnswerID: 514223

Follow Up By: olcoolone - Wednesday, Jul 03, 2013 at 21:22

Wednesday, Jul 03, 2013 at 21:22
X2...... my guess as well.

It is better to have a drive line out of alignment physically then to have it in alignment..... but too much can makes it worse.
FollowupID: 793148

Follow Up By: Ross M - Wednesday, Jul 03, 2013 at 21:36

Wednesday, Jul 03, 2013 at 21:36
I Agree, All universal joints must operate with some amount of driveline angle. If a uni runs dead in line, then it lasts only until lunch time as the rollers do not move and they burrow into the hard surfaces of the cup and trunnions.
The centre bearing unit on a Dmax is made to be 12.5mm off centre so even if the load brings the unis inline, ie. looking horizontally, they are always slightly offline sideways (vertically) and therefore always made to have an angle in all three unis so they last.

FollowupID: 793150

Reply By: Ashez H - Wednesday, Jul 03, 2013 at 22:25

Wednesday, Jul 03, 2013 at 22:25
Hi Les,
The others are on to it by the sounds of it.
I had the same issue with my bt50 (2010 model) after fitting an old man emu suspension.
The centre bearing will need to be lowered in order to correct the angle. Unfortunately for me I had to do this by packing some washers in the mount with limited thread availability. The good news for you is that your 2012 bt gives you plenty of thread to play with. The even better news is that ARB make a spacer kit specifically designed for this issue.

By the way, the quick way to test this is to put a load in the back and test drive. The load will push your driveline angle closer to whee it would have been prior to the lift.

Hope this helps.

AnswerID: 514236

Follow Up By: Member -Shakeejob - Thursday, Jul 04, 2013 at 10:56

Thursday, Jul 04, 2013 at 10:56
Thanks to all for the information.
You seem to confirm what I suspected.
I am having the issue examined by a drive line expert but I will be armed with the wealth of advice supplied and have a fair idea of what questions to ask.

Thanks again.


FollowupID: 793182

Follow Up By: Ross M - Thursday, Jul 04, 2013 at 20:03

Thursday, Jul 04, 2013 at 20:03

What is a "driveline specialist"?
A reputable, well known driveline service centre or a reselling wharehouse like ARB, TJM OP, ETC, ECT.

ARB do make something for the centre bearing in the form of a special nut, but the spacing method is SUS. Judging by the trauma had by one person who had their system installed and washers used as packers, it didn't seem to be a professional job. They still had vibes, a destroyed centre bearing rubber unit and other issues as rear uni angle not correct.
FollowupID: 793237

Follow Up By: Member -Shakeejob - Friday, Jul 05, 2013 at 17:01

Friday, Jul 05, 2013 at 17:01
Ross M,
The information I have been given is that Driveline Services Australia, in Acacia Ridge will be having al look at the situation. It seems that they are fairly well set up ( from their website at least). They don't seem to be a cowboy outfit at any rate, so we will see.
I am back in WA (by air ) for a week or so and will get the Ute to them towards the end of the month.

FollowupID: 793321

Follow Up By: Isuzumu - Thursday, Jul 11, 2013 at 21:12

Thursday, Jul 11, 2013 at 21:12
There is nothing wrong with the Sax Suspension, we have 25 K thru the GRR and the Savannah Way thru Roper Bar.
I can not recomend this suspension highly enough, maybe you should have brough a D.Max hahaha

FollowupID: 793734

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