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Mazdaspeed Archive => Suspension => Topic started by: bigx5murf on December 31, 2011, 03:28:26 AM



Title: Broken Rear Sway bar bracket, how?
Post by: bigx5murf on December 31, 2011, 03:28:26 AM
I was hooning it and heard a real un-nerving sound, turns out the studs for my rear sway bar bracket got snapped off the rear sub frame.  I had just installed the 949 adjustable endlinks about 100 miles ago.  I guess I must've adjusted them wrong, I had it about 3/4" shorter than stock endlinks.  Car is 12.5" rear and 11.75" front.

The 949 endlinks were only installed in the rear.  I'm going to hold off installing the front until I know what I did wrong so I don't repeat this.

(http://i5.photobucket.com/albums/y199/BiGx5MurF/1325298884614.jpg)
(http://i5.photobucket.com/albums/y199/BiGx5MurF/1325298932985.jpg)


Title: Re: Broken Rear Sway bar bracket, how?
Post by: Woofster on December 31, 2011, 04:21:20 AM
Those endlinks are mighty sturdy and certainly compared to the stock ones.  I've used them on the front of my car for a couple years with a 1.25" tubular bar and NEVER had an issue.  Maybe you preloaded the bar to tight (some feel there shouldn't be any when the car's off the ground)?   


Title: Re: Broken Rear Sway bar bracket, how?
Post by: bigx5murf on December 31, 2011, 04:25:33 AM
I had the endlinks adjusted to shortest they'll go while still being able to lock em.  Doesn't shorter take out pre-load?


Title: Re: Broken Rear Sway bar bracket, how?
Post by: SilverMiataRacer on December 31, 2011, 05:38:29 AM
Actually you might have made them too short.  If you get droop on one side and no droop on the other and the endlink is adjusted short I would think it's possible to be pulling down on the bar and break off the mount when it doesn't want to go.  Then again it's late and I'm tired so I might be wrong.


Title: Re: Broken Rear Sway bar bracket, how?
Post by: bigx5murf on December 31, 2011, 06:10:29 AM
Well, I couldn't find any guides on proper endlink adjustment.  I just used my floor jack to raise up the LCA, then set it so that rear sway was parallel to the LCA.  What's the correct way to adjust endlink?


Title: Re: Broken Rear Sway bar bracket, how?
Post by: Lokiel on December 31, 2011, 07:09:42 AM
^
I put the car on stands, lie under the centre (front or rear), reach the endlinks (one per hand) and tighten (or loosen) them by spinning their shafts just tight enough so that there is only the faintest sway bar load on both of them, then I tighten the lock nuts onto the shaft. It's easy to do it this way since you can quickly feel if you need to tighten or loosen either of the endlink shafts and can "feel" that they're both loaded the same.


Title: Re: Broken Rear Sway bar bracket, how?
Post by: bigx5murf on December 31, 2011, 06:03:07 PM
But won't the bar load up once you lower the car doing it this way?


Title: Re: Broken Rear Sway bar bracket, how?
Post by: newold_m on December 31, 2011, 10:03:17 PM
better to do it with the car on ramps or crawl underneath so the suspension is properly loaded.


Title: Re: Broken Rear Sway bar bracket, how?
Post by: Lokiel on January 01, 2012, 02:09:30 AM
better to do it with the car on ramps or crawl underneath so the suspension is properly loaded.

- redone now using ramps to put some load on the bar!


Title: Re: Broken Rear Sway bar bracket, how?
Post by: bigx5murf on January 01, 2012, 04:08:34 AM
So how do you guys recommend repairing this?  Weld on new studs, or drill it out and use some grade8 or grade 10 bolts to hold the bracket?


Title: Re: Broken Rear Sway bar bracket, how?
Post by: SilverMiataRacer on January 01, 2012, 05:11:15 AM
I'd drill it and use bolts and nuts


Title: Re: Broken Rear Sway bar bracket, how?
Post by: Scotty on January 01, 2012, 08:08:48 AM
^ Use bolts and nuts.

You might be able to hammer the broken stud out with a punch, but I couldn't.

I'm on my third year with a bolt/nut setup for one of mine with no issues.


Title: Re: Broken Rear Sway bar bracket, how?
Post by: SilverMiataRacer on January 01, 2012, 05:12:57 PM
I had broken a stud for the rear mount on one of my NAs.  I had to drill it out from the backside and then used a nut and bolt and it's been on there for about 15 years now.


Title: Re: Broken Rear Sway bar bracket, how?
Post by: bigx5murf on January 04, 2012, 03:43:27 AM
Drilled out and replaced with bolts today.  Hopefully the other side holds.


Title: Re: Broken Rear Sway bar bracket, how?
Post by: Tobra on February 10, 2016, 08:11:05 PM
I guess this is not a super common problem, but I had one break too.  Better to drill from back of the car to front or front of car to back, or maybe it does not matter.


Title: Re:
Post by: Tickittyboo on February 11, 2016, 01:35:05 AM
I also broke one. Drilled it from back of car towards front. Doesn't really matte, just get it out. No issues for m using a bolt.

Wow, old thread.


Title: Re: Broken Rear Sway bar bracket, how?
Post by: Jeff Goji on February 11, 2016, 01:47:34 AM
I accidently snapped one many years ago on my 91, these bolts are unbelievably weak. Drilled it out from behind and replaced it with a bolt and nut setup.


Title: Re: Broken Rear Sway bar bracket, how?
Post by: '95MSM on February 11, 2016, 02:36:20 AM
I'll detail the racer's setup to end link setup, but it is beyond the resources of most people. Your take-away from this should be to get the car as level as possible, with the best alignment possible, then set the links so there is no pre-load. I'm not obsessive about having the anti-roll bars ends exactly level, but if they are tilted, you'll usually get a slightly different roll rate at one end of suspension travel vs. the other. If you have that going on at both ends of the car, you can get some interesting behavior during squat and/or dive. Setting the ARBs so that they don't bind all the way through full droop to full compression is way more important than keeping them from being tilted.

So if you have the resources:

1) Roll the car onto a known level surface, or at least 4 level-to-each-other wheel-pads. Linoleum floor tiles make great shims, and as long as there are Italian cafes in the world, you should be able to find black/white checker tiles for that extra "competition" look.
2) Disconnect front and rear sway bars
3) Deflate shocks if so equipped
4) Set ride height
5) Set corner weights, recheck 4) and repeat as necessary
6) Re-connect sway bar end links with zero pre-load
7) Set shock pressures

I go through this routine with the S2 before every race weekend.

I picked up a "next step" evolution from a former SCCA National Champ, but you have to have an alignment platform to realistically pull it off. Steven Johnson would setup his alignment platform and scales at every event. Before the first session, he would confirm the corner weights that he set back in the shop, then after every session, he would confirm that they have not changed significantly. Any significant change means the car has changed and you need to understand why. That was how SJ stayed in front of a shock going soft, or a suspension mounting point drifting, or any number of things that most often aren't found until the car does something vicious entering a corner.