Polybushing a MK2 MR2
Polybushing a MK2 MR2
This is a workshop guide for replacing the old tired rubber bushes in your 89-99 MK2 MR2 with shiny new poly-urethane bushes. You follow this guide at your own risk and I take no responsibility for incorrect ordering of parts, grazed knuckles, lost weekends, broken limbs or snapped bolts. Just because this is the way I did mine, doesn't mean it's the right or correct way to do it. Your mileage may vary, etc etc.
Bushes
Lets get this out of the way first off: Polybushes are not meant for road use. Cars ship with nice soft rubber bushes to improve ride comfort, ironing out the bumps in the road and suchlike. These polybushes remove a lot of compliancy from the suspension and make your ride harsher. However, replacement rubber bushes are not easy to come by, and the ones on your car are almost certainly old and tired. These cars are all at least 11 years old now, and so are the rubber bushes. So, it's a halfway house between replacing old parts and tightening/stiffening up your suspension. Once installed, your steering will feel tighter and turn-in will improve. You should have a full wheel alignment performed following the installation, and the person performing the alignment should be made aware that the car has been polybushed, so as to alter the standard alignment to take the removal of compliancy into consideration.
I chose to use Prothane poly-urethane suspension bushes. You can get these from Peter at SBits, who will make sure you get the right parts for your car.
Other manufacturers of bushes and bush suppliers are available
You must make sure you order the right bush kit. The bush kit for the rear of the MK2 MR2 is the same on all revisions. Rev1 cars have a different front bush kit due to their front control arms being slightly different. This guide covers installation of the Rev2-Rev5 kit, but the front arms are the only difference. There are various sizes of anti-roll bar used on the MR2, you should make sure you order the right size bushes for yours. You can find this out a number of ways - easiest is to read the size which is stamped into the side of the standard ARB bush. You could also use a set of calipers on the bar to measure its width. However all Rev3+ turbos have 19mm ARBs.
I received from SBits:
1 rear suspension bush kit
1 front suspension bush kit 92+
1 rear antiroll bar bush kit 19mm
1 front antiroll bar bush kit 19mm
And here's the contents, laid out. ARB bushes are in separate packaging to the left, the bushes for the front of the car are along the top, and the rear of the car along the bottom. Also included was 6 sachets of teflon grease and 4 large washers.
Note, there are an extra set of bushes on the rear than the front.
You Will Need
The above pictured bushes
A hefty breaker bar
A torque wrench
Whatever size socket is required to remove your wheels, + locking wheel nut if applicable
10mm socket
14mm socket
17mm socket (should be 1/2" drive and 6-sided, NOT deep)
19mm socket (should be 1/2" drive and 6-sided, NOT deep)
24mm spanner (or VERY deep 1/2" drive 6-sided socket)
A thin 14mm spanner
A hacksaw
A vice or workmate
A blowtorch and plenty of gas
A decorators breathing mask
A flathead screwdriver
Possibly a stanley knife
Lots of WD40 or Plusgas (plusgas preferred)
Various jacks and axle stands
This job will take a full day. Be prepared to find out things about your car you didn't want to know. This could be anything from bent suspension to failed balljoints!
Here's a diagram of where the bushes go. Bushes are highlighted in red/brown, yellow is the anti-roll bars and green is where the large flat washers are to be installed. Please excuse the crapness of the diagram!
So, off we go.
Front Bushes
Crack your wheelnuts.
Jack the car up, using axle stands on the sill jacking points. Don't support the car on the front crossmember, front central jacking point, or the rear subframe, as these all need to move.
Once the car's in the air, remove the front wheels.
Get under the car and remove the undertray that protects the steering rack and front suspension arms. It looks like this and is held on with a myraid of 10mm bolts:
Some of these bolts may snap, as they've been exposed to the elements for many years. If you've worked under an MR2 before you'll be more than familiar with this! Plenty of plusgas will help prevent snappage.
With the undertray removed you can get access to the front suspension arms and front anti-roll bar. You should coat the fixing points for the front arms and the front ARB brackets with the releasing agent of choice (from here on in I'll just say Plusgas). You'll need to spray it on:
Front ARB bolts x4
Balljoint -> Hub bolts x4
Lower arm -> Front Crossmember bolt x2
Front arm -> Front bracket bolt & nut x2
Unbolt the 2 17mm bolts securing the balljoint to the underside of the hub. You can just about see them in the background of this shot. Do not try and undo the 2 nuts that bolt the 2 front arms together (shown wet in this picture). They will just spin and there is no need to seperate the 2 arms, they will come off and go back on as 1 piece.
Unbolt the 17mm bolt securing the front arm to the front bracket.
Unbolt the 19mm bolt securing the lower arm to the front crossmember.
With a bit of persuasion you should now be able to remove the arm from the car. You might have to hang off it at this point to get it to release, especially if the front arms are slightly out of shape.
At this point you can check out your balljoint and make sure there's no play in it.
Put your decorators breathing mask on. Using your blowtorch, burn the 2 rubber bushes out. Do this away from the car, the rubber comes out in really small melted bits and they'll stick to your paintwork. The rubber will probably need some encouragement from a screwdriver to come out. It takes about 10 minutes per bush.
After a while you should be left with this all over the floor:
Scrape the rest of the rubber out of the cups on the end of the arms - it should come out cleanly. You'll notice that in the cup on the front arm there is a metal collar:
This needs to come out. Grip the arm either in a workbench or vice. Disconnect 1 end of your hacksaw blade, pass the blade through the cup and reattach it to the saw. Cut 2 slots in the cup, 1 all the way through and 1 partway through to act like a hinge:
Once you bend a bit of the collar out with a flathead screwdriver it will come loose and can be removed:
Your front arm should now look like this:
Installing New Bushes
When installing polybushes you must use the teflon grease supplied. You only need apply it very thinly, on any surface where polybush meets metal. So, the inside of the bush where the metal sleeve fits needs some, the outside of the bush where it sits in the cup needs some, and the end of the bush where it will touch the body of the car needs some. You should also try and keep the bushes as clean as possible - this is quite difficult when they're covered in grease! As long as you avoid getting any grit in there they should be OK. However small sharp pieces of grit or stones could easily tear a bush.
Each bush consists of a metal sleeve and 2 parts. I found it easiest to install 1 side of the bush into the cup, then fit the metal sleeve through the middle, and finally push the 2nd half of the bush in from the other side. Some of them were quite a tight fit!
Insert the new bushes into the arm. You can't really get this wrong, the bushes and metal sleeves are all unique sizes. However the slightly 'flatter' bushes go in the thicker, lower arm, and the more pointy ones go in the front arm. They should've come with the metal sleeves in them which helps you not mix them up.
At this stage you might be wondering what the large flat washers are for. The bushes all have metal inserts in them for the bolts to sit in - the thicker, lower arm also had a flat plate on one end. This is to stop the bush deforming under braking, when weight transfer throws all the weight to the front of the car. The washers are fitted like so, on the front face of the bush to replicate the flate plate in the original bush:
This makes them a real pain to get back on the car, but perseverence is key.
Reinstall the arm. I found it easiest to fit the lower arm into the front crossmember first, with its washer. This is because you can use the front arm to lever the whole assembly about to make the bush and the washer line up. This bolt is 87 ft-lbs, 118 Nm. Then refit the bolt + nut through the end of the front arm. You'll find a jack handy here, you can apply pressure to the arms to get everything to line up as it would be if the car were sat on the ground. They should be done up to 83 ft-lbs or 113 Nm. Finally reattach the balljoint to the hub, believe it or not the BGB says 8 Nm for the fronts and 113 for the rears. I went with the values for the rears all round (83 ft lbs, 113 Nm).
Repeat on the other side of the car!
Front Anti-roll Bars
The front ARBs are just held on with U shaped brackets and 2 14mm bolts per side. If you sprayed these with plusgas when you removed the undertray then they should be pretty free by now and won't snap. Mine were fine (they are covered with the undertray so are protected) but I've snapped these on a rusty MK1 before.
Undo both bolts and drop the bracket and the bush off the bar. Only do one side at a time or the anti roll bar will fall on your head :lol:
You'll note that the stock bushing has a slit cut in it to allow you to fit it over the bar - my Prothane front ARB bushes didn't have this so I cut them with a stanley knife, in the same place that the stock bush was cut. However the rear ones were pre-cut so I think that's just a manufacturing error on the ones that I had. Again, these should be greased on the inside and outside. Fit them back onto the ARB (you might need to clean it first if the old bush has left any **** behind). Clean the inside of the bracket and bolt it back up. These 2 bolts should be 14 ft-lbs or 19Nm.
Once you're done you can reinstall the undertray and move to the rear of the car.
Potential Pitfalls
This is where I said you might find out some things about your car that you didn't want to know
One of my front arm assemblies was an absolute pig to remove. I knew something was wrong when the bolt securing the lower arm to the front crossmember came out looking like this:
The bush in the lower arm looked like this:
And upon removal:
When I installed the new bush I noticed that the arm was slightly deformed. In this picture you can see part of the cup protruding around the edge of the bush, on the right.
Tony Bones at WIM confirmed that this arm was bent when performing a wheel alignment on my car. New ones are expensive!
Rear Bushes
As you can see from the diagram in my first post, the rear arms are a slightly different design. They include castor adjustment to move the wheel backwards and forwards in the wheelarch by means of a large threaded section on the end of the forward arm, to change the point at which it meets the rear arm. However the fundamental idea when replacing the bushes is the same.
Remove the rear wheels.
Remove the 2 rear-most undertrays. Driver's side, the one that covers the oil filter and aircon compressor, passenger side the one that angles air up towards the gearbox.
Plusgas everything. You will need to loosen the rearmost nut where the 2 arms join each other while the arm is still on the car. This is 24mm and you'll need a spanner or a VERY deep socket to get it off. Mark everything up beforehand so you can get it all aligned back again as it was.
Loosen the rearmost nut only! Don't touch the one on the front of the threaded section. Undo the nut almost to the end, until it is free enough that you can undo it without too much force. It's an interference fit as it's used for fine wheel position adjustment so it is quite tough.
Once that's loose you can undo the rest of the rear arms. Unbolt the 2 17mm bolts securing the balljoint to the underside of the hub. The lower arm bolts to the subframe, again with a 19mm bolt. There is a hole in the subframe where you can spray plusgas to aid undoing the bolt:
This is quite difficult on the RH side of the car as the oil pan is in the way :lol: A shallow socket or a 19mm spanner are needed here.
The forward arm bolts into a bracket at the front of the engine bay with a 17mm bolt and nut:
Again, this is more difficult on the driver's side as the oil filter (on a rev3+) is in the way! Be careful not to punch a hole in the side of the filter with your sockets.
You might have to undo some of the handbrake cable brackets for complete access.
Again, by rocking the arm about a bit you should be able to get it off the car:
At this point you can again check out the state of the balljoint. You should now separate the 2 arms. The bush between the two arms is constructed like so:
You can see that this bush is a bit more like the polybushes in construction - it's already in 2 pieces with a metal sleeve inside it and washers at either end. I found that on 1 side of my car the metal sleeve had become 1 with the forward arm and needed a lot of persuasion before it would come off.
You will reuse the washers when installing the new bushes. They go together like so:
Don't forget the grease! Obviously you only fit one half of the bush at this stage, because the other half will go on the other side of the lower arm when it's all bolted back together, just like the original bushings. The remaining bushes in the end of each arm should be removed and the new ones installed as per the front bushes. By which I mean fire!
They fit like so:
Again, you will want to install the thicker, lower arm with a washer on the front of the bush (i.e. facing the front of the car) to prevent spreading under braking. This is the same as the fronts. Don't reinstall the arms yet if you are also changing the rear ARB bushes.
Rear Anti-Roll Bar
The bushes for the rear ARB are a right pain. You'll probably have noticed that they are attached to the rear subframe:
What you need to do is this:
Unbolt the 3 14mm bolts in the centre of the rear subframe that hold the rear torque mount on.
Reach up onto the top of the subframe and feel around the exhaust mount for 2 10mm bolts. Undo them.
The subframe is held on with 4 long 17mm bolts, 1 in each corner. Undo 1 bolt all the way until it comes out, then bolt it back in 2 turns. Do this with the 3 remaining bolts too and you'll have dropped your subframe as far as you can without removing it (it's heavy!). This should afford you access to undo the top bolt for the ARB bracket, with your thin spanner. The head of the bolt is also very low profile and it's all a bit fiddly. You don't need to totally remove the bracket, you only need to loosen the subframe bolt enough to move the bracket out of the way.
It's quite likely that the rearmost bolt on the rear ARB bracket will just snap off - it is exposed to the elements and mine were quite rusty. In this case you can just punch it out of the bracket (it's held in with 3 tiny spotwelds) and put a new nut & bolt through the bracket.
Once you've done the rear ARB bushes, do the bolts up to 14 ft-lb, 19 Nm and then reinstall your subframe. I did it this way:
Do the 4 main 17mm subframe bolts up until the subframe is about 5-10mm clear of the body.
Reinstall the 3 torque mount bolts in the centre of the subframe. You should be able to wiggle the subframe from side to side now, and when it settles it will be roughly in the centre again, having been centered by the engine mount. These bolts should be 57 ft-lb or 77Nm.
Tighten the 4 main subframe bolts (83 ft-lb, 113 Nm) and reinstall the exhaust mount (15 ft-lb, 21Nm) on the top of the subframe.
Reinstall rear arms
Once you've done the rear ARB you can reattach the rear arms. This is a pig to do with the required washers. Bolt the lower arm to the rear subframe with the 19mm bolt first. I found it easier if I didn't totally tighten this up until all the arms were in place (but when you do, it's 98 ft lb, 132 Nm). Then reattach the balljoint to the hub with the 2 17mm bolts (83 ft-lb, 113 Nm). You can now install the forward arm. Slide the threaded end of the arm through the lower arm with 1 half of the bush attached, then bolt up the 17mm nut & bolt at the front (83 ft lb, 113 Nm). Then fit the other half of the bush + washer + 24mm nut on the end of the threaded section and do the nut up. In an ideal world you wouldn't tighten this nut up until the car was sat on its wheels but it's quite difficult to reach then, unless you've got ramps. However it should be 87 ft lb or 113 Nm. Double check everything is tightened up!
Reinstall your undertrays and wheels and drop the car off the jacks. Torque up your wheel nuts. Job done.
' Nothing feels quick when your other car has a 1000bhp - JamieP
Quote:A Supra without a spoiler is like a Gypsy's dog without a Nob.
this has brought back horrible memories ta
' Nothing feels quick when your other car has a 1000bhp - JamieP
Quote:A Supra without a spoiler is like a Gypsy's dog without a Nob.
That's an excellent write-up. Very detailed and informative.
Takes me back a few years to when I had a Suzuki SJ for off roading and I replaced all the bushes in the spring hangers (leaf springs of course on the SJ) with poly bushes. Some of those bushes are almost identical in there construction and I had to resort to the method you used to remove the metal collar from the front arms.
I think you deserve some rep for that :thumbup:
Great write up, I made the mistake of looking via the mobile yesterday - not mobile friendly!!!!
Nice work
Excellent write up .. and just to re-assure the public and members of the Royal Society for the Prevention of Cruelty to Spanners, said tools were given appropriate protective clothing, suitable recreational breaks and assessed for Health and Safety precautions. Sadly a few did meet their demise during the course of this production as is the nature of Spanner Life in Mr Toxo's Garage .. they will be sadly missed and our thoughts go out to their relatives, RIP boys