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Help me understand grade bolt rating

I went ahead and replaced both rear leaf packs on the Jeep cherokee this weekend. Some of the bolts had to be heated and taken off others had to be cut. The bolts I replaced them with were grade 8.8 metric as they were the only size I could find with the length needed to get them through the perch then through the eye of the spring then through and into the inner welded nut on the inside of the frame ( shame on you , the engineer for this design) I was worried the welded nut was going to spin off inside the boxed frame but did not ( no way to get to it ,other than cutting through the inside floorboard , down into the boxed frame). At any rate, is the 8.8 grade,not the same or better as the SAE 8 grade bolt? I was thinking it was a higher grade bolt since , well , the number was higher. After researching , Ive found the 8.8 may be less or the same as a grade 5 SAE bolt? 

Thanks

Comments

  • I’ve always known the 8.8 to be roughly equivalent to a grade 5 and the 10.8 to be comparable to grade 8. I’ve applied this logic to the metric fasteners in various situations and never had an issue. By the way, I love cherokees. They ar infinity capable for what they are. I had an 88 with a 3” lift and 31x10.50 mud terrains and I loved it. Had lots of fun with it. Nice driving vehicle too!
    Nicholas_23
  • edited September 2018
    OK , thanks guys. I hope the "grade 5" metrics will hold up ok in the leaf springs , I worry about them breaking off under load. I dont do heavy wheeling with this thing , the worst would be driving on some shitty side roads during the winter to get on a lake to icefish. 
    dynamoBryan@MAC
  • They will likely stretch before they break. Breaking under impact is generally in the realm of brittle materials, which hardened bolts fall into that category. You use hardened materials when you are concerned about wear or stretch, but they will shatter on a hard blow. Softer grades will be more likely to wear, stretch, and deform but less likely to actually shear or break under the conditions present in suspension. Pick your poison, basically - but I doubt you will have any real issues regardless. Torque them correctly, size them correctly, and they will likely outlast the jeep.
    Nicholas_23
    I have a signature.
  • Thanks for the info guys , I appreciate it ! 
  • My folks had 5 Cherokees over the years, only recently getting a Grand. My sister drives a Grand, but last one was a Cherokee as well. Great SUVs. My wife and I are currently closing in to get a 2015 Subaru Forester for her and replace her 2003 Liberty this week. Grands have been out of our price range or too many miles. We test drove an Equinox, and it seemed like a dog with no snappy acceleration. The Sub' on the other hand had all we asked for, and the insurance premium is pretty low to boot.

    I know it's a hijack, but anybody else have a Subaru and love it?

  • I love your Cherokee, looks great!
  • Wolf said:

    My folks had 5 Cherokees over the years, only recently getting a Grand. My sister drives a Grand, but last one was a Cherokee as well. Great SUVs. My wife and I are currently closing in to get a 2015 Subaru Forester for her and replace her 2003 Liberty this week. Grands have been out of our price range or too many miles. We test drove an Equinox, and it seemed like a dog with no snappy acceleration. The Sub' on the other hand had all we asked for, and the insurance premium is pretty low to boot.

    I know it's a hijack, but anybody else have a Subaru and love it?

    I’ve never owned a Subaru but I’ve never heard a Subaru owner complain and I’ve seen several Subaru owners go to another Subaru when time for a replacement.
  • Wolf said:

    My folks had 5 Cherokees over the years, only recently getting a Grand. My sister drives a Grand, but last one was a Cherokee as well. Great SUVs. My wife and I are currently closing in to get a 2015 Subaru Forester for her and replace her 2003 Liberty this week. Grands have been out of our price range or too many miles. We test drove an Equinox, and it seemed like a dog with no snappy acceleration. The Sub' on the other hand had all we asked for, and the insurance premium is pretty low to boot.

    I know it's a hijack, but anybody else have a Subaru and love it?

    My wife has a '15 Forester, our second. You can't go wrong. My wife works in the medical field and can't sit out work because of weather. We love it.

  • Well- I hope to as well! I just brought her home! It's a black 2015 Forester, premium trim.

    I can see me tradin' in the Mopar for one of these myself down the road...

  • Watch those 2.5 liter head gaskets 
  • Apparently that was a problem with the older EJ engine. The newer FB does not seem to have this issue.

    I've already read about the class action suit for oil consumption of 2013-2014, and the cam-chain chatter issues that occur around 30k miles. This car seems to not have the chatter (it's at 64k), and the exhaust did not make my hand black when checked. It appears that most that had the oil consumption problem were manual transmissions, and this one has the Lineartronic CVT. I'll monitor the oil level for certain.

    Experiences;

    The electric-steering is very responsive, and it's a benefit to not have a power steering pump.

    Oil filter, AC compressor, alternator, etc are all in front on top of the engine for easy access and maintenance.

    Lineartronic CVT is really nice! No feeling of shifting or revving from gear to gear even under acceleration. It just feels like a infinitely variable forward gear.

    Full coverage insurance is really inexpensive, due to being a very safe car.

    24/32mpg.

    Thus far, I'm only faulting it for being VVT, and a DOHC, BUT- there aren't many vehicles out there that aren't at least one of these criteria anymore.

  • edited September 2018
    One of my coworkers has that same year and model and loves it.  He did however say that he doesn't get anywhere near that MPG.  I've ridden with him and he doesn't have a lead foot so I don't know...  I liked riding in his Sub overall.  Very simple controls, not a lot of electronic gadgets to go wrong.  Rode nice, good visability, etc.  If my wife didn't require hauling other peoples kids around (read minivan with 3rd row of seats) I'd seriously consider one for her.
  • One of the first cars I got to work on was a Sub boxer motor.  Me and a buddy rebuilt his mid 70s Sub, 30 over and added a cam.  It was a blast from stop light to stop light.  I bought one used and thrashed it about for years, I ended up selling as I was hot on hondas at the the time.

    I was hot on Subarus a few weeks ago when my son brought over his new WRX.  Under the hood it is really impressive, there is a lot of technology in those motors.  The fancy Dunlop tires have a cool rim protection rubber bump that I had never seen before.
     John H, btw forum has decided I don't get emails
  • Ooh! WRX are cool... I've always kinda liked the Outbacks too; flat-6 vs 4cyl is a plus. I think CJD also drives (drove?) a black WRX, as he had it at InDIYana the last year at the Hyatt. That was a slick car!!

    I also noticed something on the Forester I haven't seen elsewhere. There are circular shrouds on the disc brakes around the back-side of the assembly. That's a new one on me.

    My dad was also very impressed. He and I went to do the final check of everything before I signed on the dotted line just for another set of eyes in case I had missed something. It never hurts! He has talked to people in passing about their Subarus for years, and not one has complained. He said that would be a possible alternative when the Grands weren't affordable we were looking at, though he hadn't much experience with them directly.

    I'm glad we checked them out!

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