Poor man's 3 link, got a question regarding those who have done it - Ford Mustang Forums : Corral.net Mustang Forum
 
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post #1 of 12 Old 06-19-2011, 06:34 PM Thread Starter
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Poor man's 3 link, got a question regarding those who have done it

Hello!

I've got a question for those that have done the poor man's 3 link. I have it on my car and it seems great. A great deal more traction, better ride, etc. However, I am having an interference issue with the drivers side shock. Here is some background on the car:

MM lower control arms (non adjustable)
MM Torque Arm strings (stock location)
MM panhard bar
FRPP upper control arm on the passenger side. Passenger side diff bushing is stock. Is admittedly not in the best of shape.
Bistein shocks
Converted to Thunderbird rear disks
No quads

The shock seems to be hitting the screw and bracket for the rear disc brake. The biggest concern being the screw holding the bracket to the axle. The passenger side is doing just fine.

Has anyone else had this happen, where the shock wants to hit the axle? I've searched some here and on corner carvers and have found no issues, so it seems weird. I understand there will be some side to side differences because of the nature of the setup, but again I've not heard of this. Should I just try a shorter screw/new bushing in the upper control arm, or maybe I should consider getting the quads back in the car? Thanks for any advice!

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post #2 of 12 Old 06-19-2011, 11:35 PM
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Could be from axle windup. With a TA there is no issues with the axle winding up on acceleration. The upper arms in the 4-link are there to control wind up. Now since you ditched one, and the bushings are rather old, there is a great deal of wind up. The driver side shock is hitting because the lack of the driver side upper arm.


-'90 Mustang LX Coupe 5.0 SSP. 83 DSO US Gov't Issue. H/C/I Track toy
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post #3 of 12 Old 06-20-2011, 12:36 AM
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And quads don't limit the magnitude of the windup, just its frequency.
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post #4 of 12 Old 06-20-2011, 09:42 AM Thread Starter
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Ahh well, I figured as much, but just has never heard of anyone else mentioning it and was hoping it was something simple (guess in a way it is) that I messed up. Either way, time to replace a bushing and get a new screw, see if it helps. Thanks!
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post #5 of 12 Old 06-21-2011, 03:16 PM
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I have the exact set-up with a couple of slight mods: height adjustable MM LCAs, a one-off, rod-ended upper arm for the PM3L instead of the stock upper, the SSBC T/C rear disc conversion (fox length and uses an armored solid brake line to the caliper - i.e., no flex hose), I'm running the quads and a .5" spacer on the each rear axle. I have zero deflection from my PM3L, so no hitting of the axle. I also don't have any axle tramp. The PM3L is very hard on stock bushings so they have to be monitored regularly. I agree that with this set-up, the rear articulates much more freely and forward bite is much improved.
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post #6 of 12 Old 07-28-2011, 08:31 PM Thread Starter
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Well, in my quest to get the PM3L to work for me with what I've got, I removed the screw that holds the disc brake softline bracket from the axle, and it seems better on both sides. How critical is it that that bracket be affixed to the axle? I imagine it's important (otherwise it wouldn't be there in the first place), but if I could do without it I would. If I cannot remove it, does anyone know of a way to cut some off it and affix it some other way? Thanks for any advice!

1989 Mustang GT: 5.0, 5spd --- Sold. SVO brakes, MM suspension bits, 331ci, X pipe.

2012 Mustang V6PP 6spd MT --- Daily Driver, D Stock auto crosser, maybe track days some time...
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post #7 of 12 Old 07-31-2011, 12:32 AM Thread Starter
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For reference, the bracket of which I speak in the disc brake hardline to softline bracket here:



I've read in a couple places while doing a search that the bracket can be removed with no negative effect (other than you have to be careful when removing the caliper), but few have mentioned it. Any opinions?

1989 Mustang GT: 5.0, 5spd --- Sold. SVO brakes, MM suspension bits, 331ci, X pipe.

2012 Mustang V6PP 6spd MT --- Daily Driver, D Stock auto crosser, maybe track days some time...
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post #8 of 12 Old 08-15-2011, 07:14 PM
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If you remove that bracket, I think I'd anchor the line some other way. For example, SSBC designed a full hard line from the axle union (your transition bracket) to the caliper (required the stock line to be redirected 180*). The stock anchor is used at the union, holding it tight to the axle housing. The hard-line running to the caliper is shaped like a horseshoe and armored. It goes around the shock body on the inboard side clearing it by .5" or more terminating at the caliper banjo fitting. The horseshoe design is flexable enough to permit caliper movement and pad changes but very little deflection/movement otherwise. I've not had any clearance issues in about 15 years prior to the PHB and none since. Pad changes are more complicated, especially when turning in the piston. It may not be elegant, but the design works flawlessly.
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post #9 of 12 Old 08-16-2011, 10:31 AM Thread Starter
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Thanks for the reply. I ended up removing a large chunk of the bracket and just tying it down against the axle to prevent it from moving around. In that respect, it works okay, but is nothing I consider "permanent". I did it mostly for testing the PM3L. It did stop the shock interference I was getting but the pinion was going so crazy (even with all new, albeit rubber, bushings) that I think I heard the pinion hit something, and the rear axle seal was making noise, I assume from stress from the exaggerated angles as it never did that before. I'll be replacing the rear lines with SS lines at some point in the future anyways I think.

I didn't want to spend any more money on shocks (had to get new shocks since I dimpled the heck out of my old ones at this point, they bound up like crazy), tool for the bushings, and time on what is kind of a hack solution in the first place. For now I'm running both uppers and a PHB on my old H&R sport springs and just using the car while the weather is still good. The PM3L did it's job in letting me know just how lousy the quadrabind is, but I don't have funds to keep working on it or getting a TA for now. Saving for a 2012 V6 with the PP! Gotta have a new daily driver. I hope to get a TA for this car at some point though, because those few moments I could push the car with the PM3L and TA springs, it was a real sweet handling car (comparatively, at least).

1989 Mustang GT: 5.0, 5spd --- Sold. SVO brakes, MM suspension bits, 331ci, X pipe.

2012 Mustang V6PP 6spd MT --- Daily Driver, D Stock auto crosser, maybe track days some time...
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post #10 of 12 Old 08-16-2011, 02:02 PM
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Quote:
Originally Posted by That89GTGuy View Post
The PM3L did it's job in letting me know just how lousy the quadrabind is, but I don't have funds to keep working on it or getting a TA for now.
I know. I had no idea how badly the stock suspension hindered the car's handling until I put on the PM3L and got it sorted. What a difference. I'd really like to modify an s195 upper 3-link set-up (I have the arm and chassis mount - pretty much sits where stock pinion bumpstop mounts) rather than use the T/A. The packaging is so much lighter and compact. On the other hand, the MM T/A is a proven design and relatively easy to install. I'm still undecided but there is no way the stock stuff is going back in; that is history.

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post #11 of 12 Old 08-22-2011, 11:25 AM Thread Starter
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While I'm aware that these forums are not a blog, but I wanted to get some information put out there for future searchable reference for others.

I recently got the car to an autocross for the first time (without something breaking immediately after arriving) with my PHB and both uppers (forced to since the PM3L wasn't cutting it), and I have a few things to comment on:

The panhard bar really improves the "feel" of the rear. It definitely gives you the feeling of greater communication and better control... to a limited point. I'm talking maybe 5 tenths, then things get real bad, real fast. Here is a quick rundown of what I've got in it right now:

Stock style front suspension with bilstien struts and H&R sport springs, MM camber plates with their recommended alignment for a street car, stock sway bar, and that's about it. The front weights a bit less than stock with a smaller radiator (single core aluminum), aluminum heads, AC and smog equipment removed, and fog light bracket removed. Tires are 245/50/16, I don't remember the exact type but they are Falkins max performance all season (bad, I know)

Rear suspension consists of MM PHB, Thunderbird(SN95) length axles/discs, H&R sport springs (stock location), bilstien shocks, MM standard non-adjustable lowers with stock sway bar, FRPP uppers, passenger side diff bushing is new, drivers side diff bushing is worn but in decent repair. Tires are the same as the front.

The autox was on a pretty rough surface (partially abandoned road course surface turned into grid for a nascar course), as well as being pretty high speed in some places (about 70mph+). I knew this setup wasn't as good as PM3L or even the stock setup in terms of compliance after my first run, but I didn't have any issues with it. My second run I pushed a bit harder, and got bit by the rear bind something fierce around a high speed left the rear just suddenly decided to snap oversteer. With the amount of speed I had and the rough surface, I was unable to catch it and went into the grass. No damage, but I had to tip toe the rest of the day, constantly trying to get the rear to stay behind the front.

I've done that course before with an almost exactly same setup, just minus the PHB, and never had issues like I had recently. Sure, the rear was vague, but at least it could articulate a bit. The only other change was the wider axles, but if where to do anything significant, I would imagine it would be to increase rear grip and cause increased understeer.

Maybe it works at track days with really sticky tires, but while the PHB plus both uppers may "feel" better than stock, I don't believe it helps the bind situation at all, and would recommend that and PHB install should be followed by a TA/3 link very shortly after. I you can't afford to do both at once, wait until you can.

1989 Mustang GT: 5.0, 5spd --- Sold. SVO brakes, MM suspension bits, 331ci, X pipe.

2012 Mustang V6PP 6spd MT --- Daily Driver, D Stock auto crosser, maybe track days some time...
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post #12 of 12 Old 08-24-2011, 04:31 PM
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FWIW, I agre with the above recommendaiotn to convert to the T/A, PM3L or true 3-link when doing the PHB swap. With that said, during an A/X driving class both me and the instructor did at least 4 180+s with my PHB/PM3L (rod-ends) and the MM adjustable sta-bar. this was due to my not realizing that the rear Bilstein shock bump was all but used up at my then ride height of 25.5". When the shock could go any further, the system bound big time and with the MM bar snapped the rear end around with little warning. the iinstructor was saying I needed to soften the rear bar which was at the softest setting . Because I had front tire rubbing issues, I raised the car and with just another .25" of ride height the rear shocks didn't bind and the whole system worked so much better it was like a compltely different car. I need those sn95 Bilstein shocks with more bump travel.
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