U bolt nuts for for XT

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31 Oct 2012 21:26 #1 by dandjcr
dandjcr created the topic: U bolt nuts for for XT
Forum Home > OKA Maintenance > U bolt nuts for for XT

fran Philipson
Member
Posts: 9
We have lost a nut off the stud on the front axle. It looks the same size as the U bolts. Does anyone know the size and thread?
George
July 24, 2011 at 5:23 PM Flag Quote & Reply

Peter & Sandra James Oka 374
Member
Posts: 412
According to the LT parts manual they are 16mm, doesn't measure the thread pitch though. From memory they are a fine pitch.
--
Oka 374 LT Van

July 24, 2011 at 6:02 PM Flag Quote & Reply

joseph baz
Member
Posts: 331
Fran,it should be 16x1.5mm,u bolts could be 16x1.5 or 5/8x18tpi as some people fitted after market US made u bolts(hope I haven't confused you)
Cheers,Joe
July 24, 2011 at 6:25 PM Flag Quote & Reply

fran Philipson
Member
Posts: 9
Thanks for the replies, we will try to chase one up on our way through Swan Hill today. Regards Fran and George
July 25, 2011 at 8:50 AM

David and Janet Ribbans - Oka 148
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09 May 2018 14:02 - 09 May 2018 14:08 #2 by OKA in Africa
OKA in Africa replied the topic: U bolt nuts for for XT
After two broken spring blades in Kasane, Botswana it has been now time to do a proper repair of the spring blades in South Africa.
My friend tried to tighten the U-bolt nuts as indicated in the OKA LT manual. So, what is the correct torque?
In the section 10:2-4 'suspension' the U-bolt torque is indicated with 190NM.
In the section 10:3-3 'suspension' the U-bolt torque is indicated with 152NM.
In the section 'torque specifications for nuts & bolts ...' the U-bolt torque is indicated with 168 NM.
All of the the above seems to be an excessive torque.
As you can see from below picture, one of the weldings at the center braked already broke.
What is your experience or advise? Excessively torque the nuts up to 168NM or rather do it "by hand" and "feeling"?


Thank you and best regards

OKA #327 in Africa
www.oka4wd.com/forum/members-vehicles-pu...47-oka-327-in-africa
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Last Edit: 09 May 2018 14:08 by OKA in Africa.

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09 May 2018 15:27 - 09 May 2018 15:30 #3 by dandjcr
dandjcr replied the topic: U bolt nuts for for XT
OIA, yes the manual does say do them up to some ridiculous torque, similar to wheel nuts.

I think 190NM (140 ft-lbs) is way too much, as you've found. I do them up to around 90-100ft-lbs (135NM ), the limit of my torque wrench, and even that seems very tight and starts bending the spring mount wings (and probably stretching the U-bolt). A dab of Loctite would probably stop any loosening (there are no lock washers), or adding an extra locknut.

New springs will need to bed in for a while so I would do the nuts up alternately by "by hand" and "feeling" until they feel tight enough. Then recheck them after a few 100kms. The centre bolt of the spring pack should keep them in place even if a bit loose.

Be careful of the drivers side front however, the studs into the diff housing might stretch and break.

My U-bolt nuts used to work loose but that was when my spring hangers and bushes were worn and the springs could move around a lot (mostly the front of the front). Once I fitted 20mm pins and neoprene bushes all round (in 2009) there is next to no lateral movement of the springs and the U-bolt nuts don't come loose anymore.

There are a few more U-bolt snippets from 2010 here .

David and Janet Ribbans - Oka 148
Oka148 profile here.
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Last Edit: 09 May 2018 15:30 by dandjcr.

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09 May 2018 15:42 #4 by Holmz
Holmz replied the topic: U bolt nuts for for XT
There are a few reasons for doing them up tight.
However only one of the reasons includes "to keep them from coming loose".

If that is the main driver, then the Nord-Lock washers may help fulfil that effect?

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11 May 2018 12:30 #5 by mort
mort replied the topic: U bolt nuts for for XT
Hi OIA,
I didnt know the Torque required and have had mine off some time ago and tightened to what I would think appropriate for the size of bolt and its use which is mostly how I do it except when it comes to head bolts etc then I will check the settings.
My curiosity got the better of me and I have just checked what mine are and all but one was approx 150 NM with one being 164 and really I dont think that is excessive.
Looking at the photo which is different to mine which is an LT you have a gussett on the right side and need one on the left but it will be a shame to burn off that nice paintwork.
Martyn

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11 May 2018 23:04 - 11 May 2018 23:13 #6 by dandjcr
dandjcr replied the topic: U bolt nuts for for XT
OIA, when I bought a new spring clamp from Oka (front left), it had double fillets at each end, either side of the U-bolt hole. I subsequently welded extra fillets to all my spring clamps which didn't have them (they varied), and that prevented further bending.

The "wing" on yours seems to be much shorter than normal and the paint job is unusual. Were they a special?

Also your nut seems to be distorted/flattened at the bottom. Through over-tightening?



I seem to have fitted extra flat washers, maybe the U-bolts had stretched. I subsequently replaced all the U -bolts (made by a local spring manufacturer) when I fitted airbags.


David and Janet Ribbans - Oka 148
Oka148 profile here.
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12 May 2018 08:31 #7 by Holmz
Holmz replied the topic: U bolt nuts for for XT

dandjcr wrote: ...
I seem to have fitted extra flat washers, maybe the U-bolts had stretched. I subsequently replaced all the U -bolts (made by a local spring manufacturer) when I fitted airbags.
...


Do you have a place to recommend?
And a model - or does one just supply a drawing?
I might as well get nuts from a similar place if I do new mounts for airbags.

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12 May 2018 10:59 - 12 May 2018 11:01 #8 by Alister McBride
Alister McBride replied the topic: U bolt nuts for for XT
Holmz, any decent spring place will have what you're after, if you're not handy with a welder then they could make the saddles too... and possibly get it engineered depending on your wallet! You can buy grade 8 thread for the studs on the pumpkin of the front diff but they need to be machined like attached pic (helps with stress concentration in such a short stud). The rest of the U-Bolts you may as well get the spring joint to make as they have different length U-Bolt 'blanks' ready for bending and it is very quick for them to do.


cheers, alister
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12 May 2018 11:37 - 12 May 2018 11:54 #9 by dandjcr
dandjcr replied the topic: U bolt nuts for for XT

Holmz wrote: Do you have a place to recommend?
And a model - or does one just supply a drawing?
I might as well get nuts from a similar place if I do new mounts for airbags.


I just took my old ones to Industrial Springs in Adelaide and they made them up and (I think) supplied new nuts too. They'd probably do it from just the dimensions and application (weight/strength).

Cost in 2009 was $15 each.

[Industrial Springs made/reset my new springs, but went into decline due to import competition and sadly no longer do bespoke manufacture. They are worth a call though, 0403 151 628, as they seem to be rebuilding that capability. They used to have the drawings and specs for Oka springs].

David and Janet Ribbans - Oka 148
Oka148 profile here.
Visit our technical and travel blogs: here.
Last Edit: 12 May 2018 11:54 by dandjcr.
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12 May 2018 18:58 #10 by Holmz
Holmz replied the topic: U bolt nuts for for XT

Alister McBride wrote: Holmz, any decent spring place will have what you're after, if you're not handy with a welder then they could make the saddles too... and possibly get it engineered depending on your wallet! You can buy grade 8 thread for the studs on the pumpkin of the front diff but they need to be machined like attached pic (helps with stress concentration in such a short stud). The rest of the U-Bolts you may as well get the spring joint to make as they have different length U-Bolt 'blanks' ready for bending and it is very quick for them to do.



cheers, alister


Thanks (I think... I sense this is important, but I have not connected yet.)
Where does that stud go?
The ones I have are U shapped.

Being in the centre... all the springs places are all equidistant.

I am ~handy with a welder.

The fronts is riding low, just about with the bore tusks scraping up the dirt for tubers,
Hence airbag perches may be worthwhile.

You mentioned grade-8, which is an imperial or SAE thing. The rest of the world equivilent is 11.8 .
I noticed my spare spring bolt says 8.8, which is an SAE grade-5.
There are standard 16-mm.
Mort's 19-mm
The 22-mm
And the OKA parts 25 (1") spring pins.

I used a mag-base drill today for a "jackstand". But would rather avoid redrilling spring bolt holes.
Hence maybe upgrading the 8.8 bolts (grade-5) to 11.8 (grade-8) seems one possible approach.

Other approaches include higher strength bolts than Grade-8... these include some very expensive examples, but there is no requirement for new bushes, new holes, and grinding off old bolt-head retrainers and attachment of larger bolt-head retainers. So maybe the super high strength bolts are "good value"?

Back to U bolts....

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13 May 2018 15:39 #11 by Alister McBride
Alister McBride replied the topic: U bolt nuts for for XT
Hi Holmz,

The U-Bolts imperial, so it's grade 8 imperial (see below). The stud photo is an example of how you would machine the stud which goes into the pumpkin of the front diff to reduce stress concentration on the bolt (it's not actually a photo of mine). Yours may still be fine anyway but i needed a new one... Seriously, i would get a spring joint to do all the rest of the U-Bolts (and/or the above studs), they have the right blanks and the machinery to do it easily!
See:
www.boltdepot.com/fastener-information/m...olt-grade-chart.aspx
for bolt grades, 1psi = 0.00689476MPa (just use an online converter if necessary)

ok, didnt realise you were talking about doing shackle pins too... yes, drilling them is a PITA and don't use a D-handle drill as the elongated holes from the 16mm bolts grab the bit and nearly break your wrists! (mine were sore for some time after drilling all mine!) And, yes that is the problem with the standard 16mm shackle pins is that they not only wear and break, they also elongate the hangar hole. When i redrilled mine the wide part of some of the oval elongated hole was slightly bigger than my 20mm drillbit!

I used 8.8 20mm bolts for my shackle pins, they will never break. They are drilled and have a grease nipple for greasing the bushes.

The saddles can be fabricated yourself although for front airbag mounts it is harder to setup than the rear saddles, there are a few who have done them and they might want to chime in here. Although for legal liabilities you might want to get a spring shop to do them. Rear ones are quite useful for 'campsite tilt-ability' and load support, i did rears, not fronts, my front springs are pretty good. Just be careful as the rear brake proportioning valve could get confused if you have airbags in the rear suspension...

cheers, alister
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27 May 2018 06:05 #12 by Holmz
Holmz replied the topic: U bolt nuts for for XT

OKA in Africa wrote: After two broken spring blades in Kasane, Botswana it has been now time to do a proper repair of the spring blades in South Africa.
My friend tried to tighten the U-bolt nuts as indicated in the OKA LT manual. So, what is the correct torque?
In the section 10:2-4 'suspension' the U-bolt torque is indicated with 190NM.
In the section 10:3-3 'suspension' the U-bolt torque is indicated with 152NM.
In the section 'torque specifications for nuts & bolts ...' the U-bolt torque is indicated with 168 NM.
All of the the above seems to be an excessive torque.
As you can see from below picture, one of the weldings at the center braked already broke.
What is your experience or advise? Excessively torque the nuts up to 168NM or rather do it "by hand" and "feeling"?


I would put a triangular gusset underneath the edge of it, near the bolt.

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