Grease

Submitted: Thursday, Dec 13, 2007 at 13:14
ThreadID: 52517 Views:3881 Replies:4 FollowUps:5
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About 6 weeks ago I had the pads, rotors and front wheel bearings replaced on the GQ.

Then I did a trip to the Pyrenees and a bit of mild 4x4-ing up and down the hills and then back home.

Back home I discovered thick oil/grease leaking out from the back of the backing plates.

Today the stubs were stripped down again and mechanic reckons that the grease had turned to oil. He said that he had put the right High Temp Wheelbearing grease in originally.

Faulty grease? Bad seals(not Nissan seals)

Anyway, jobs done again. They had ordered new seals but the wrong ones were sent up(the joys of living in the country) but luckily I had an OEM set in my shed courtesy of a Nissan mate who had thrown them out.

So I will see how the new seals and grease go this time around.

Cheers

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Reply By: Chris & Debbie - Thursday, Dec 13, 2007 at 14:23

Thursday, Dec 13, 2007 at 14:23
Were the axle seals replaced as well? if these are worn they will let diff oil through to mix with the wheel bearing grease.

Cheers
AnswerID: 276413

Follow Up By: Peter 2 - Thursday, Dec 13, 2007 at 14:45

Thursday, Dec 13, 2007 at 14:45
Willem I'd suspect the the diff/axle seals as well if they filled with oil so quickly.
I'm not familiar with Nissan diffs but on cruisers there is a seal in the axle tube just behind the CV bulge which should be replaced especially on the 'long' side as the axle flex's more on that side and wears the seal out.
I was also told by several mechanics years ago not to use HTB grease in 4wd hubs as they do not run hot enough to melt the grease. Was told to use Castrol APX or similar, the same on trailer hubs as again they do not get hot enough to melt the grease.
This came to light when I questioned why the bearings were badly scored after 30k's on a new vehicle, I repacked with HTB before a long 20k 3 month trip, bearings on both truck and camper trailer were buggered by the time I got home.
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FollowupID: 540318

Follow Up By: Willem - Thursday, Dec 13, 2007 at 17:16

Thursday, Dec 13, 2007 at 17:16
No, the axle seals on the birfiled joint side were not replaced as they weren't leaking. The stub axle was not removed.

The seals which come with the wheelbearing kit however were replaced initially and now again.

Noty sure of the brand of HTB grease

Cheers
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FollowupID: 540333

Reply By: Bushtrek - Thursday, Dec 13, 2007 at 16:51

Thursday, Dec 13, 2007 at 16:51
Willem,
It would be useful to know which bearing grease was used here, and whether the hubs were over packed with grease.
Wheel bearing grease as you probably know, does not liquefy unless it is diluted with oil, or overheated well beyond its "Drop Point", or the hubs are over packed with the result the oil that is sheared out of the grease during use does not have sufficient time/space to re-absorb into the grease structure.
If Castrol greases are preferred either HTB or APX-T grease is suitable, except the HTB has an indefinite drop point, whereas
APX-T has a drop point of 260 Celsius, meaning both are well above the working temperature of the hubs/bearing set.

Contrary to the myths that many subscribe to, it is not the fact that the grease is heated to its melting [drop] point that releases oil to the bearing surfaces, it is the shearing action on the grease when the lubricated surfaces are under load that 'squeezes" the oil out of the grease structure.
Cheers
AnswerID: 276432

Follow Up By: Willem - Thursday, Dec 13, 2007 at 17:23

Thursday, Dec 13, 2007 at 17:23
Thanks for that explanation.

I will ask the mechanic next time I see him exactly which grease he has used. They work on a lot of country 4x4's including farmers 4bies, roo shooters, Epic Energy vehicles and should know what they are doing.

It remains to be seen what happens next. Going to the east coast via some dirt roads next week but most likely won't be doing 4x4 stuff. In May 08 I will be giving the wagon a work-out again across about 300km of unchartered and trackless spinifex and hopefully everything will be sorted by then.

Cheers
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FollowupID: 540335

Reply By: ian.m - Thursday, Dec 13, 2007 at 21:37

Thursday, Dec 13, 2007 at 21:37
hi , are far as i know lithium based and bentone based grease:s are never to be mixed one will turn the other to oil, need to totaly wash and dry all parts in contact if unsure of which base grease used. have been in trade long time and have seen benefits of both grease's but my choice is always apxt, very good water resistant properties. and thats my thoughts.
AnswerID: 276523

Follow Up By: Bushtrek - Thursday, Dec 13, 2007 at 23:53

Thursday, Dec 13, 2007 at 23:53
Ian.m,
Of course you are quite right.
I assumed Willem's mechanic knew what he was doing and fully cleaned out the system before replacing the grease.
Willem has essentially confirmed this, but your point is valid.
One small point... APX-T is a Lithium complex soap base grease which is different to conventional Lithium base, nonetheless it is not compatible with a clay [Bentone] base grease such as HTB.
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FollowupID: 540442

Follow Up By: Member - Phil G (SA) - Friday, Dec 14, 2007 at 08:28

Friday, Dec 14, 2007 at 08:28
"I assumed Willem's mechanic knew what he was doing and fully cleaned out the system before replacing the grease"

I thought it was common practice to simply push the new grease in which pushes the old grease out. Saves the mechanic a heap of time.
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FollowupID: 540461

Reply By: Member - RockyOne - Sunday, Dec 16, 2007 at 10:57

Sunday, Dec 16, 2007 at 10:57
Re grease..I got a top mechanic,here in Emerald,Qld,in around '95 to fit a Detriot locker in the front diff (disc braked) of my Rocsta swb..Diff based on,it appears Dana 27's. About a year later (and a lot of offroad'n fun) we were having smoko,when one of the crew reckoned front,right wheel is leaning. Jacked it up. All the outer bearing was shrapnel including the cage. The disc brake was stopping the wheel falling over & coming off. (Dangerous! Front right wheel..The one facing on coming traffic) Checked with a lube rep. Mechanic had put black Low Speed grease in (ok in UV joints,even though they spin fast,yet the actual bearing surfaces cover very little distance with good air flow,Steering etc) instead of dedicated High Speed grease.$600 later,new brngs/seals,freewheel hubs,I added Wynns red Ultra-Supreme grease (not soap based.handles water well) and 12 years later,brngs still like new.Like our 1980 Diahatsu F-55,(we got it new) always greased with red Wynns.here 27 years later,still has original UV joints,wheel,king pin bearings spite of creek crossings where water came in the cab air vent flap above the bonnet.Diesel.Suggest you guys read label of Wynn's® Ultra-Supreme. BOL !
AnswerID: 276892

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