Poly Bush? Just say NO
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Thread: Poly Bush? Just say NO

  1. #1
    SENIOR ROVER Bolt's Avatar
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    Poly Bush? Just say NO

    I have had a pleasant day in my new shop building working on the front end of "Bolt" (2002 White)
    Replaced all of the front end bushings except Pan Hard Rod.
    Got some nice ones on Ebay. 80 bucks complete and all hardware was British, rubber parts were good looking Indian made.
    I have been aware the poly bush's were failing for some time, but the only symptom to show up was recently, when the front axle rotated at about 80mph whilst slowing down, and the front U joint cross pieces rattled on the flange.
    Had a look, and stopped driving it pending my shop being built. (Hot here, and did not want to work in the sun)
    Basically the Poly bushes which are about 8 years old, but have maybe 20k miles on them turned to blue gummy powder.
    In the photo of the whole group, you can see one black rubber bush from the rear of the control arm which is a factory original. Still serviceable!
    So much for the claims that they can outlast factory by 5 times! HA!Poly Bush? Just say NO-imgp0157.jpg
    Poly Bush? Just say NO-imgp0160.jpgOh, and these have not been used hard off road, nor have they been subjected to any kind of salt, chemicals, or petroleum products. Just water.
    1952 Austin Champ (Hawaii)
    1953 Austin Champ (Australia)
    1985 Classic w/ Tdi300 (Australia)
    2002 4.6 HSE, White "Bolt" Hawaii Daily driver. Now the "Boat Car" here on the West Coast
    2002 4.6 HSE Borrego Yellow "Digby" Wife has absconded with Borrego as the Dog Taxi

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  3. #2
    JUNIOR ROVER
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    Re: Poly Bush? Just say NO

    Fully agree with you but for the LR bushes you need the special tool. Not viable for DIY guys, me think.
    P38 - 1997 2.5 DSE
    CLASSIC - 1982 ,2.4 VM DIESEL(In complete Project-sold)
    TOYOTA CORSA -1998, 1.5 TURBO DIESEL (sold)

    Haven't heard of Murphy's Law, go buy a RANGE ROVER.!

  4. #3
    SENIOR ROVER Bolt's Avatar
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    Re: Poly Bush? Just say NO

    The bushes I got had nylon shells and were a bit oversized to get started into the bore.
    I suspect they require some sort of compression sleeve to be inserted as designed. A bit of a turn on my field Lathe (Bushing on a bolt a drill motor, and a disk sander...Failure was not an option) and I installed a deep chamfer on one end, and whittled them down just a bit in overall dia.
    Used a borrowed bushing tool from O'Reilly auto parts and was able to slide them in with minimal fuss, so these at least are a Diy.....If you are willing to re work them a bit.
    Steel shelled bushes would need an arbor press, but that is just a machine shop charge, and you are done. Easy job either way.
    1952 Austin Champ (Hawaii)
    1953 Austin Champ (Australia)
    1985 Classic w/ Tdi300 (Australia)
    2002 4.6 HSE, White "Bolt" Hawaii Daily driver. Now the "Boat Car" here on the West Coast
    2002 4.6 HSE Borrego Yellow "Digby" Wife has absconded with Borrego as the Dog Taxi

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  6. #4
    JUNIOR ROVER
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    Re: Poly Bush? Just say NO

    I have the same plastic shelled ones.
    The deep chamfer, about 5 mm?
    Also, got the front axle ball joint installation/ removal tool, may be I can use that.
    P38 - 1997 2.5 DSE
    CLASSIC - 1982 ,2.4 VM DIESEL(In complete Project-sold)
    TOYOTA CORSA -1998, 1.5 TURBO DIESEL (sold)

    Haven't heard of Murphy's Law, go buy a RANGE ROVER.!

  7. #5
    FRESHMAN ROVER
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    February 5th, 2019
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    Re: Poly Bush? Just say NO

    Wow! That's scary to say the least. Nice Work!

    I take it your still in the bay area? Let me know when you are free, I wouldn't mind dropping off those air springs I promised you.
    2001 4.6 HSE

  8. #6
    SENIOR ROVER Bolt's Avatar
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    Re: Poly Bush? Just say NO

    So, ya made it back from Pismo! Good job! How was it? New sneakers work out well in the soft stuff?
    Yep, still pinned down by the persistent gale force winds from the NW, so a bit of light maintenance.
    You are welcome to come by and drop air bag, whatever day works best for you. (Sunday?) Also, you need to take another spin in the white beastie. MUCH improvement!
    It was doing well, and you did not really notice the bad bushes since it was a slow motion failure, but WOW! the "After " is amazing!
    The ride with EAS has been called a Magic Carpet. Mine was a bit frayed about the edges and I did not realise until I did the bushings just how GOOD it can be!

    Kapilamuni, I basically took off 50% of the nylon shell for about 8mm in a shallow taper, then took off about 25% of the shell for the remaining width of the shell. (yours could be different, but you get the basic drift?.......)
    If you leave too much, the nylon will bulge out as you press it in. I also put a light coating of grease on the shell and bore. The tool I borrowed was actually for ball joints, but was robust enough to crank in the bushings. I had to use the large cupped washer with the large hole from the rear mount of the arm with the press as it, being cupped, helped to compress and squeeze the last bit of the bush into the bore. Went as far as I could, flipped the washer over and used the back shoulder to push it flush into the bore.I would bet that my "Plan A" which was an Grade 8 bolt, some washers, a 1 1/4 in socket, and a nut would work as well. The nylon shell really compresses nicely. Slid right in, but stayed firmly in place. First one took about an hour, the next 3, 15 min each.
    I would like to see what the proper tool for installing these nylon shelled bushes looks like. Meantime, I am back on the road, and VERY happy camper!

  9. #7
    JUNIOR ROVER
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    Re: Poly Bush? Just say NO

    The proper tool has a internal taper so as the bush is pressed through it, the outer sleeve is reduced in diameter so it slips in. The outer race from a 30306 bearing has the correct dimensions so can be used at a push.
    96 4.6HSE
    98 4.0 Police spec
    and a number of others I maintain for the owners.

  10. #8
    SENIOR ROVER Bolt's Avatar
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    Re: Poly Bush? Just say NO

    Thanks!
    I figured it had to be a basic funnel shape to get the bush to squeeze down as it entered. Makes sense.
    That or a set of sleeves, one to hold the shape and one to push.
    1952 Austin Champ (Hawaii)
    1953 Austin Champ (Australia)
    1985 Classic w/ Tdi300 (Australia)
    2002 4.6 HSE, White "Bolt" Hawaii Daily driver. Now the "Boat Car" here on the West Coast
    2002 4.6 HSE Borrego Yellow "Digby" Wife has absconded with Borrego as the Dog Taxi

  11. #9
    FRESHMAN ROVER
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    Re: Poly Bush? Just say NO

    Yes! I managed to make it back in one piece. It was fun, the tires did excellent. I managed to get stuck once. I was cut off by some ATV's and lost forward momentum, but I reversed myself out of that situation so I never actually had to be towed out. This machine is amazing, so many people got stuck and I just cruised right on by.

    I'll give you a call later today, I'm actually heading to Modesto today so I wouldn't mind making a small detour and see the much improved Bolt
    2001 4.6 HSE

  12. #10
    JUNIOR ROVER
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    Re: Poly Bush? Just say NO

    Thanks Bolt.
    Must give it a try as I'm on Polybushes for the last few years. With the Richard's idea of taper bearing shell, should be doable.
    P38 - 1997 2.5 DSE
    CLASSIC - 1982 ,2.4 VM DIESEL(In complete Project-sold)
    TOYOTA CORSA -1998, 1.5 TURBO DIESEL (sold)

    Haven't heard of Murphy's Law, go buy a RANGE ROVER.!

  13. #11
    JUNIOR ROVER
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    Re: Poly Bush? Just say NO

    Quote Originally Posted by kapilamuni View Post
    Thanks Bolt.
    Must give it a try as I'm on Polybushes for the last few years. With the Richard's idea of taper bearing shell, should be doable.
    Your also need some large washers and a bit of 12mm studding with nuts to pull them through.

  14. #12
    FRESHMAN ROVER
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    Re: Poly Bush? Just say NO

    Bit more detail on the taper race method, the video's not great, but is my first youtube attempt

    https://rangerovers.pub/topic/1340-r...ensions?page=1

    https://youtu.be/RiAycOtZOwQ
    1998 Defender 50th 4.0L V8 Auto
    1998 Range Rover 50th 4.6L V8 Auto
    Toylander Series 2A

    Previously
    1980 SIII 2.25 petrol
    1997 200 Tdi CSW

  15. #13
    FRESHMAN ROVER
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    Re: Poly Bush? Just say NO

    I made the big mistake of buying the Laser Tools bush fitting set as the blurb said it would to do P38 bushes as well as other Land Rover models. Unfortunately it doesn't although some of the spacers could be useable. Laser polite when told but refused to offer a refund. Annoying.

    Set to and made up my own set of tools which work well enough although I'd do a couple of things differently if starting over. PM me if you'd like a set of drawings in PDF format. Need access to a respectable lathe to make the set. Could be done on SouthBend 9 or Myford but life is too short.

    Also included is one for the height sensor pivot pin as these can rust out to the point that the link doesn't move freely. I habitually make a new pair of height sensor pivot pins in stainless steel before attempting radius arm refurbishment. My score is around 25% too bad to re-fit. As they are so easy to make if you have a decent lathe about the place its not worth the risk of being caught out.

    Impressed by romanrobs taper bearing outer race technique. I'd have expected trouble from the bush trying to tilt sideways as it enters the taper but clearly its not an issue if you are careful. That impact wrench is working really hard tho'.

    The whole polybush thing annoys me intensely. Along with so may other "racers do it so it must be good" bodges. Thirty seconds contemplation of what happens when a P38 rolls should be enough to demonstrate that the whole idea is flawed as ploybushes won't have compliance in the required directions and must inevitably destroy themselves to generate roll clearance. Roll is a PIA to deal with all except pin joint geometrically perfect suspension systems anyway. Not such an issue for the race boys as their cars are wound up so tight on hard suspension that they pretty much don't roll anyway.

    I always find it a bit scary to see how little there is actually holding two tons of truck to the wheels. All rubber too. If you analyse the design its a lot stiffer and stronger than it looks. But those big radius arm bushes work hard for their living.

    Clive

  16. #14
    JUNIOR ROVER
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    Re: Poly Bush? Just say NO

    Thanks Clive, got your PDF with full info. I don't have a lathe but will get it done soon. These days I'm tight with transmission, replacing 4HP22 with a 4HP24.
    P38 - 1997 2.5 DSE
    CLASSIC - 1982 ,2.4 VM DIESEL(In complete Project-sold)
    TOYOTA CORSA -1998, 1.5 TURBO DIESEL (sold)

    Haven't heard of Murphy's Law, go buy a RANGE ROVER.!

  17. #15
    FRESHMAN ROVER
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    Re: Poly Bush? Just say NO

    Having watched romanrobs video I'm inclined to think that loctiting the taper bearing outer race into a tube or concentric pair of tubes would be a much easier way of making a compressing device with a nice guided entry to keep the bush straight than machining one from solid as I did. Basically start with a (very) thick wall tube whose outer diameter is greater than the bearing race and inner diameter the same as that of the taper race at its large end. Bore a short length at one end out as required accept the taper race with its small end flush with the end of the tube.

    Although machining the tapered tool was quite easy on my lathe I'd almost certainly have used the taper race instead if I'd thought of the idea or seen romanrobs' demonstration before I made my kit.

    Odds are that tube the right size isn't available so either the bore will need adjusting to match the top end of the race or it will need to be built up from two, or maybe three concentric tubes. About an inch or inch half sticking up beyond the race should be plenty to support the bush ensuring that it goes straight in. Would work fine in a press too. Far too easy for the bush to tilt out of line if using the naked race in a press. As anyone who has ever done the bush change in a press has found, holding the radius arm in the right place and keeping things straight tends to need extra hands!

    If you follow romanrobs' method use the finest thread pullscrew you can find. Bushes are 1/2" bore, standard cheap puller sets use either M12 or 1/2" UNC which are 1.75 mm pitch and 13 tpi respectively. 12 mm fine is 1.25 mm pitch and 1/2" UNF 20 tpi which will reduce the torque needed to pull the bush in by roughly 1/3rd. Well worth it, especially if using ordinary spanners. I'd probably make a 26 tpi special to more or less halve the torque as I have both the gear to make one and a stash of 26 tpi nuts to fit.

    Need to revise my drawing set to show the taper race in tube system as an alternative to machining from solid.

    Clive

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