so pulled the trigger...

M Body General Discussion

  1. picklesgarage

    picklesgarage Member

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    so wife and I bought an 86 5th Ave the other weekend. body is in fantastic shape for a new england car, minus someone's attempt at buffing the trunk after the clear had peeled. the interior needs the headliner and pillar trims recovered but nothing major. the 318 has already been converted to electronic ignition and the computer control disconnected. drove it home 70 miles without too much problem. so i feel i have a good if not great base to start with. after looking it over on a lift found some things that explained the ride home, like the play in the steering being due to lateral play in the output of the steering box, simple fix. planning to rebuild the front end since most of the bushing have seen better days. was thinking poly was the way to go for that. i would like to wake it up a bit, doesn't need to be a bruiser, but both my vans and my Shelby Charger put it to shame. from the quick reading ive done here already seems quickest and cheapest is to start with the gearing. the other things i was going to start with would be intake/carb and exhaust. i'll post more in the exhaust area asking about that. what else should i be looking to do to improve the car over all?
     
  2. Duke5A

    Duke5A Well-Known Member

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    Is this a daily driver? What kind of money do you have to spend on it? After we know these two we can give you accurate advice.

    Poly bushings squeak, and I mean a lot! The upper control arms and a few other places have poly. You can bounce the front end and the entire damn car squeaks. lol.
     
  3. picklesgarage

    picklesgarage Member

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    Leaning toward daily or at least when it's not snowing out.
    Does rubbing two dimes together count as a budget? I know there are things that will have to wait. Would like to get it safely back on the road for now at least. I had heard they can be noisy. Would you suggest using stock style replacements then for the bushings? The only replacements I found for the torsion bars were poly. I'd like it to ride nice and handle well.
     
  4. Opticon77

    Opticon77 Well-Known Member

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    A) "Ride nice" = Rubber bushings for reduced NVH and don't do anything too low-profile or high-load with the tire sidewalls.
    B) "Handle well" = sway bars and good shocks as a start. Then steering ratio/tightness and chassis rigidity.

    After that point A and B will start to conflict with each other. Things like higher spring rate, polybushings, iso-delete, and less sidewall flex will sacrifice ride for handling.
     
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  5. picklesgarage

    picklesgarage Member

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    yes there is always a compromise between the two. doesnt mean that there isnt a middle ground. one where the car handles well but isnt squeaking when you lean on it. i had heard for more then one person that polys tend to be noisy, some is ok but if it is typically that extreme with this chassis rubber sounds like the better option. the plan with tires for now will probably be stock. not really the preference but its a compromise to get other things done and get to driving. by the way is it 5x4.00 or 5x4.50 on the bolt pattern? finding conflicting info on different sites. think they are mixing up the fwd new yorkers with being rwd
     
  6. Opticon77

    Opticon77 Well-Known Member

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    5x4.5" otherwise known as 5x114.3mm
     
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  7. Oldiron440

    Oldiron440 Well-Known Member

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    It's 5 on 4.5, as far as the squeaking I don't what to here the suspension going over a speed bump.
     
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  8. Opticon77

    Opticon77 Well-Known Member

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    Straight poly bushings require a good silicone w/ PTFE grease. The manufacturers usually offer lubes with great sticking power and having a zerk fitting in the surrounding sleeve like much of the FirmFeel stuff makes service easy. There are also companies like PST making graphite impregnated poly bushings that are supposedly self-lubricating. I haven't played with those yet.
     
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  9. BudW

    BudW Moderator Staff Member

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    The front suspension bushings fall under four (4) areas, to consider:
    - Upper and lower control arm bushings.
    - Sway bar bushings (frame and at torsion bar).
    - Torsion bar bushings (pivot (K-frame) and end (control arm)).
    - Shock bushings.

    My opinion as to bushings. Urethane (or polyurethane, which might be the same thing?) are wonderful for suspension systems – but they do have a cost (ie: ride quality). Thirty years ago, I installed all poly bushings into my ’68 Charger and my ’69 Road Runner. I didn’t get my Road Runner completed to know much about it (had to sell car to pay for a divorce, in an incomplete state). The Charger was extremely rough riding afterwards, using 15” tires (this was thirty years ago…). I ended up switching out the control arms (all 4) after replacing bushings with rubber, first. I then sold existing (poly) arms to a friend. I was so much happier afterwards, without much difference in handling. With urethane bushings in upper and lower control arms – I could feel every leaf, bug and grain of sand I drove over – or more importantly, so did my kidneys. That would be a bigger issue, now I'm thirty years older (sigh).

    I’m a firm believer of having/using rubber for the control arm bushings (upper and lower).
    That said, I will use only urethane for sway bar bushings. Rubber has “too much” give. Ride quality is not affected one iota for either bushing type, but sway bar does come into action much quicker (almost as if you have a faster steering gear).

    A person can disconnect the sway bar (something many drag racers do, because of weight and it allows faster weight transfer from front to rear on takeoff), but you will find on a hard turn, the car rotates excessively, almost to the point if feels like door handles are about to grind against the pavement on hard turns.

    Torsion part bushings are different. The factory had either regular rubber bushings for control arm ends and middle (pivots) and for police use, firmer bushings for both. The firmer police bushings evaporated just after ’89 (M body production stopped). The regular rubber bushings have recently evaporated (last couple of years) – so the only available torsion bar bushings now are urethane (unless someone has a hoard of new rubber bushings, somewhere). I hadn’t had the pleasure of working with urethane torsion bar bushings, yet – so can’t offer much comment there.
    In my opinion and experience, urethane pivot bushings should work excellent. I would think rubber would work better for the end bushings (to control arm), sense you wants a little give there – but hadn’t heard anything negative, so far.

    Shock bushings wear out, just like shocks wear out (look at upper right corner of fifth picture down). I have friends who will replace the (new) rubber shock bushings with urethane. Personally, I don’t know that it makes a hill of beans worth of difference on shock bushings, sense shocks are there to dampen bumps and to keep car from bouncing after a bump. Most new shocks come with rather hard bushings to begin with. My opinion is to use what comes with your new shocks and you should be fine.

    Now what will make an even bigger difference is with replacing the rubber K-frame mounts with Cast Iron (Mopar Performance), with aluminum (FFI, for example) or with urethane. I think a metal would work better than urethane – but any of the above will make a huge difference over the rubber (even new rubber, if you could find any.
    20160411_153503 B.jpg
    These rubber bushings shown are in better condition than most I've seen.
    20160914_125656.jpg
    FFI versions. Nice, but pricy.


    Rear suspension is a different matter.
    I’m not aware of anyone making urethane rear suspension front oval-shaped bushings. The oval bushings are an issue in of itself. The same oval bushing was used for ’83-07 minivans – so a supply of bushings will not be a problem for the foreseeable future.
    Bushing modified.jpg
    If rear leaf spring is removed for any reason, for my own cars (or friends), i recommend inserting two bolts/studs/rods (ie: something solid) marked by red arrows - into the two holes, and re-install (per side). That will firm those bushings up, a lot.
    If you are going to have new leaf springs made, I recommend using the round (rubber) front bushings (‘60’s B-body) and you should be good.
    Ft Leaf Bush.jpg

    If you see any cracking or rubber issues, in any of the rear bushings, go ahead and replace with new bushings.
    Again, I recommend with rubber, for I don’t see, except for in a full-time race car possibly, that urethane bushings will improve anything but increased noise.


    Now the ISO-clamp, is a different issue. That system did nothing for performance, did nothing for ride quality, and did nothing for improved part longevity. IMO, it makes cars with a tad (or more) performance hop more, makes any handling piss-poor, makes ride quality worse (when new, even worse with a few decades are on the clock), and the lower “U” shaped bracket is a known part failure (at blue circles).
    IMG_2456a.JPG

    Replacing any FMJ rear suspension ISO-Clamp system with an older style shock plate (or FFI ISO eliminator, or similar) will improve getting power to the ground (with those capable of traction issues), improves handling, improves ride quality, it gets rid of the troublesome lower ISO clamp (“U” shaped bracket) and it raises the rear suspension about ½”/13 mm (because of removal of upper rubber biscuit mount). The rubber biscuits have not been made for a couple of decades.

    Now many members have replaced the rubber biscuits with urethane ones and have had good luck with them, but you still have the troublesome “U” bracket to worry about.
    ens-5-6106g_xl.jpg
    I firmly believe that even on an /6 car (like Ole Yellow, for example), removing the ISO-clamp with older shock plate, ISO eliminator or using urethane biscuits, will help the ride . . . a lot.
    BudW
     
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  10. 80mirada

    80mirada Well-Known Member

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    Firm Feel makes a urethane oval front bushing set for our cars. I have them, should be a picture in my 80 Mirada thread
     
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  11. picklesgarage

    picklesgarage Member

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    BudW thanks for all that. im pretty sure im going to go with rubber for uppers and lowers, may now use the poly for the sway bar. since i cant seem to find anything other then poly on the torsion bars that seems like thats how its going to go. hadnt put much thought into the k frame bushing since they look pretty good. i knew i was going to have to do something in the rear since one of my ISO clamps has a crack down the middle, was just going to make some new plates but the more i read and the move advice i get seem the way to go there is to remove them.
     
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  12. BudW

    BudW Moderator Staff Member

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    The rubber K-frame bushings allows for a lot of movement, before car starts to turn.
    On a hard turn, I can feel the K-frame move, before the front tires move – most noticeable on back to back hard turns Left to Right (or vice versa).

    If you are going to run car hard on street or racing that has turns involved, get rid of those rubber K-frame bushings and go solid (or urethane). Well worth the effort.

    Some FMJ cars, the K-frame might be cracked or has poor welds where the steering gear attaches to it, so it is always a good idea to have someone move the steering, both directions (a good ¼ turn, both ways) several times, while someone else (ie: you) with a flashlight, watches the steering gear area for any movement (other than the shaft attached to steering wheel). Many of these K-frames get cracked (hitting a pothole just right, etc.) or has poor welds (from factory), that just get overlooked.

    Several here (and I) recommend welding in extra gussets, and make sure all K-frame welds are good and complete, anytime the K-frame is out of car. Yes, it is a pain, but well worth it in the end.

    I might even say to get K-frame stress-relieved after the welding (optional), and give it a good paint job (or powder coat, or whatever) before install.

    Do that while engine is out, get the bushings/ball joints replaced, etc. and it will feel like a completely different car.

    Also, a great time to consider an FFI steering gear rebuild (stage I, II or III) or replace with a Borgeson steering gear (newer Jeep retrofitted to fit our cars). Our steering gears first came out in 1960 and had improved (only) a tad over the years (last used in ’03, in B-vans). Add in the slop from driving them a bit, and you find out your existing steering gear is, um, err, not up todays standards.
    If your car has three cat converters (like my ’86 Fifth Ave), I also believe the heat from those cats causes the gear seals to melt and leak fluid. The P/S fluid runs out of my Fifth Ave almost as fast as I can put it in. I have a Rebuilt TTI Stage II gear for it – just too lazy to install it (as well as TTI aluminum mounts, and so forth).
    I want to get rid of those cats, first. Those buggers will have a faint red glow to them after a long drive.
    BudW
     
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  13. picklesgarage

    picklesgarage Member

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    not seeing any listing off hand for urethane k member mounts. im probably just missing them some where. seem like replacing them will have to be an upgrade at some point. unfortunately the solid mounts and or the firm feel boxes are out of our price range at this time.
    i do have the mini cats and i do need to address the exhaust but im going to wait on that since exhaust doesnt matter if you cant drive it.
     
  14. Raff

    Raff Well-Known Member

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    I just recently went through most of the front end on my F wagon. Moog rubber bushings for the upper/lower arms. Poly for the sway bar and k-frame mounts.
    Energy Suspension Sway Bar Bushings 5.5110R
    Prothane Body Mount Bushings 4-101-BL
     
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  15. picklesgarage

    picklesgarage Member

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    Raff. thanks for the insight.
     
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  16. Oldiron440

    Oldiron440 Well-Known Member

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    Does anyone have the thickness for the solid top bushing not including the top pad for the Kframe mounts?
     
  17. Raff

    Raff Well-Known Member

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    4171E74B-5A93-4BAD-ACFF-F32E571E8C49.jpeg
    Not sure how accurate you need it. The bumper shock is in the way when I took the pic but the upper part of the poly bushing is a little over 1 1/2 inches thick. I had a 1 1/2 inch piece of metal which fit between the k frame and the frame rail with a little wiggle room