rkymtnflyfisher
Trout Bum
Were you in Missoula last Monday? I'm thinking we passed by each other on Russell St., I was driving my 40.
Builds Another Prado in Montana (3 Viewers)
- Thread starter AirheadNut
- Start date
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- Thread starter
- #322
I didn't end up welding on the frame extensions, I just bolted the bumper up to the existing holes in the frame. I'm not sure how much was cut off the bumper wings because I bought it with them already cut, but basically follow the inner line of the bumper through to the edge like in the photo.
Here you can see the front edge of the frame in the channel of the bumper:
- Thread starter
- #323
No, that wasn't me. There is another brown two-tone Prado like mine in Kalispell, it might have been him.
- Thread starter
- #324
My driveline angle issue has started to cause wear in the rear u-joint, so it is time to solve the problem for good. I took some measurements today; the pinion sits at 8º and the transfer case output flange is at 3º. So, I need to rotate the rear axle by 5º for everything to be happy. The way I see it there are three options:
1. Caster correction bushings. Icon makes a set of 4.6º bushings for 80-series that would fit my rear radius arm
2. Radius arm drop brackets. Likely would be custom, I haven't found anyone that makes them for the rear
3. "Washer Mod" to relocate the rearmost hole in the axle bracket
The first option would be easiest, but I haven't heard good things about the longevity of caster correction bushings, especially the high angle ones. The second option would require 2.5" drop brackets, which doesn't appeal to me as they would hang down quite a bit. Also, lots of fabrication would be required and I don't have the space and tools available right now. That leaves me with the washer mod option. According to my measurements I would need to relocate the rear bolt down about 5/8" or 16mm to get the proper adjustment. In theory this seems pretty simple, but I think getting all four holes moved the correct amount and to line up properly will be a challenge. It will also require spacers for the sway bar brackets, but that shouldn't be difficult to implement.
1. Caster correction bushings. Icon makes a set of 4.6º bushings for 80-series that would fit my rear radius arm
2. Radius arm drop brackets. Likely would be custom, I haven't found anyone that makes them for the rear
3. "Washer Mod" to relocate the rearmost hole in the axle bracket
The first option would be easiest, but I haven't heard good things about the longevity of caster correction bushings, especially the high angle ones. The second option would require 2.5" drop brackets, which doesn't appeal to me as they would hang down quite a bit. Also, lots of fabrication would be required and I don't have the space and tools available right now. That leaves me with the washer mod option. According to my measurements I would need to relocate the rear bolt down about 5/8" or 16mm to get the proper adjustment. In theory this seems pretty simple, but I think getting all four holes moved the correct amount and to line up properly will be a challenge. It will also require spacers for the sway bar brackets, but that shouldn't be difficult to implement.
GTSSportCoupe
2LTE abuser
You could make a custom rear radius arm. And then make more and sell them!
Machinist friend of mine thought that the basic shape could be water jet cut from some really heavy material. Then mill out the bushing holes to precise size. Press in bushings...done.
- Thread starter
- #326
I wish! Unfortunately I think that’s too far out of my budget, but I suppose it’s worth drawing one up and checking around with waterjet shops.You could make a custom rear radius arm. And then make more and sell them!
Machinist friend of mine thought that the basic shape could be water jet cut from some really heavy material. Then mill out the bushing holes to precise size. Press in bushings...done.
- Thread starter
- #328
That would certainly be a simple and elegant solution, but judging by the price of their 80-series radius arms it is way outside my budget.
- Thread starter
- #329
Had some time yesterday so I decided to replace my sway bar bushings. Judging by the wear on some of the bushings I suspect they were original from the factory. I pulled the rear sway bar completely out to work on cleaning and prepping for the rear axle caster correction.
Rear end link bushings: 90385-11021
Rear sway bar bushing: 48815-26040
Front sway bar bushing No.1: 48815-26020
Front sway bar bushing No.2: 48815-60030
All front sway bar bolts are torqued to 13ft-lbs. The RM183E FSM doesn't cover the rear sway bar, but I assume those bolts get the same torque.
The front and rear bushings are very similar in appearance and size, but the front ones are labeled with a 25, the rears with a 23. I believe the numbers correspond to the diameter of the sway bar.
Rear end link bushings: 90385-11021
Rear sway bar bushing: 48815-26040
Front sway bar bushing No.1: 48815-26020
Front sway bar bushing No.2: 48815-60030
All front sway bar bolts are torqued to 13ft-lbs. The RM183E FSM doesn't cover the rear sway bar, but I assume those bolts get the same torque.
The front and rear bushings are very similar in appearance and size, but the front ones are labeled with a 25, the rears with a 23. I believe the numbers correspond to the diameter of the sway bar.
- Thread starter
- #330
I finally got around to adjusting the rear pinion angle this evening. Prior to unbolting the radius arm I put ratchet straps running from each side of the axle up to the frame just in case the axle had any ideas about running away.
I used dividers and a caliper to mark out the center of the new hole to be drilled 15.6mm below the center of the original one. Once center punched I pilot drilled each side of the radius arm bracket, then worked up to a 16mm hole using step drill bits.
Rather than use large washers to reinforce the holes I made some little plates out of 1.5"x1/8" flat bar.
I used dividers and a caliper to mark out the center of the new hole to be drilled 15.6mm below the center of the original one. Once center punched I pilot drilled each side of the radius arm bracket, then worked up to a 16mm hole using step drill bits.
Rather than use large washers to reinforce the holes I made some little plates out of 1.5"x1/8" flat bar.
- Thread starter
- #331
I worked on each side individually, temporarily bolting the first side back together while I drilled and fitted the second side. That way I never had to completely unbolt the axle from the vehicle. Once both sides were drilled and plates made, I put a jack under the differential pinion, loosely installed the front two radius arm bolts and slowly lowered the jack until the rear two holes lined up. I had to do some work with a carbide burr on a die grinder to get the holes to line up with the bushings just right. Luckily the radius arm bolts are just long enough to deal with the extra width of the two 1/8" plates.
Unfortunately there was one casualty of the evening's work; the shoulder bolt that holds the pivot arm for the parking brake cable snapped off when I tried to remove it, so I am going to have to live without a parking brake until a new one arrives and I drill out the leftover stub.
Before I started on this the driveline angles were as follows:
Transfer output: 3º
Driveshaft: 6º
Pinion flange: 8º
This put the front and rear u-joint operating angles in opposition to each other, causing a lot of wear in the rear u-joint.
After reinstalling the radius arm bolts and torquing them I remeasured the driveline angles:
Transfer output: 3º
Driveshaft: 7º
Pinion flange: 3º
Giving an operating angle of 4º for each u-joint, which is a little high but should be fine. The important thing is that the u-joint operating angles are complementary instead of opposing each other like they were before. Before driving it much I need to weld in the reinforcing plates and replace the rear u-joint, but I think this should take care of the vibrations!
With the rear ends of the radius arms sitting lower in the axle brackets the sway bar no longer fits, so I need to make some spacers that move it away from the axle by about 1/2".
Unfortunately there was one casualty of the evening's work; the shoulder bolt that holds the pivot arm for the parking brake cable snapped off when I tried to remove it, so I am going to have to live without a parking brake until a new one arrives and I drill out the leftover stub.
Before I started on this the driveline angles were as follows:
Transfer output: 3º
Driveshaft: 6º
Pinion flange: 8º
This put the front and rear u-joint operating angles in opposition to each other, causing a lot of wear in the rear u-joint.
After reinstalling the radius arm bolts and torquing them I remeasured the driveline angles:
Transfer output: 3º
Driveshaft: 7º
Pinion flange: 3º
Giving an operating angle of 4º for each u-joint, which is a little high but should be fine. The important thing is that the u-joint operating angles are complementary instead of opposing each other like they were before. Before driving it much I need to weld in the reinforcing plates and replace the rear u-joint, but I think this should take care of the vibrations!
With the rear ends of the radius arms sitting lower in the axle brackets the sway bar no longer fits, so I need to make some spacers that move it away from the axle by about 1/2".
- Thread starter
- #332
Well, I greased up the u-joints today and took it for a spin. Very little vibration at first, but after a few miles at highway speed it started again, though not as bad as before. This led me to suspect either one of the u-joints or the driveshaft spline. The FSM specifies a maximum of 0.031” of runout for the driveshaft, but makes no mention of checking for play in the spline. Mine has some play, but currently I don’t have a way to measure it. I did notice that the grease zerk was missing it’s little ball bearing seal, so I need to get a new zerk.
U-joint axial play is supposed to be less than 0.002”. The rearmost u-joint will move axially in both directions, but only by a tiny amount. I may try replacing it since I have a spare on hand.
U-joint axial play is supposed to be less than 0.002”. The rearmost u-joint will move axially in both directions, but only by a tiny amount. I may try replacing it since I have a spare on hand.
- Thread starter
- #333
I took the rear driveshaft out and drove in front wheel drive to a local driveline specialist shop to have it checked out. With the rear driveshaft out the Prado was smooth and vibration free up to around 100km/h on my short drive. Within a couple of hours the shop was done, having rebalanced, straightened and painted the rear driveshaft. I reinstalled it as soon as I got home and then took it for a test drive. Vibration issue solved! It ran smooth and quiet all the way up to 120km/h.
I've still been having a little trouble with my clutch; the pedal will bottom out on the floor before it reaches full stroke on the master cylinder and the adjustment rod was maxed out as far as it would go. I stopped by a hardware store and picked up a short M8x1.25 stud and coupler nut. Unfortunately that combination adds too much length, and the pedal sits too high now. I think the best option will be to cut the little yoke off the adjuster and weld a little extension in under it.
Next on the list is adjusting the front wheel bearings. They've gotten quite loose over the past couple of months, and without a rear sway bar cornering at highway speeds can get a little exciting! The new gaskets finally arrived from Japan, so now I just need to find some time in a shop to tear into it.
I've still been having a little trouble with my clutch; the pedal will bottom out on the floor before it reaches full stroke on the master cylinder and the adjustment rod was maxed out as far as it would go. I stopped by a hardware store and picked up a short M8x1.25 stud and coupler nut. Unfortunately that combination adds too much length, and the pedal sits too high now. I think the best option will be to cut the little yoke off the adjuster and weld a little extension in under it.
Next on the list is adjusting the front wheel bearings. They've gotten quite loose over the past couple of months, and without a rear sway bar cornering at highway speeds can get a little exciting! The new gaskets finally arrived from Japan, so now I just need to find some time in a shop to tear into it.
Wow, you took it up to 120/hr?? You are patient with your testing... hahaha! 
Nice work, glad you got it resolved. I hate vibrations, rattles and squeaks!
Nice work, glad you got it resolved. I hate vibrations, rattles and squeaks!
- Thread starter
- #335
Yep! 110-120 is my normal highway cruising range, though I have gone up to 132 indicated once. With the big vibration gone I can now hear and feel the smaller squeaks and rattles; I’ve got one in the rear door and another in the rear bumper to take care of.
- Thread starter
- #336
I forgot to add: I refueled the Prado last night and was happy to finally break the 24mpg mark! 645km, 16.669 gallons, 24.0mpg or 9.8 L/100km. My speedometer reads about 3% slow, so true mileage was closer to 24.7mpg or 9.5 L/100km.
This was extremely helpful... As I have the Same Vibration and loud humming noise... I'm going to take a look at mine and see if it's the same thing.
Thanks
GTSSportCoupe
2LTE abuser
Great updates! Glad the vibration issue has been taken care of.
Try running a rear sway bar only and no front sway bar. I've found the rear end is much looser on these than the front. I never run front sway bar anymore. Just rear if I'm towing, and nothing the rest of the time.
Fastest I've had my Prado is 150km/hr (GPS and speedo indicated) on 235/85R16 at 50psi with a 2" lift only and nothing on the roof. I was using meth/water injection to get the extra hp. It actually had a bit more in it. It can't go that fast anymore now that it's on 35" tires with a taller lift. About 130km/hr max now.
That is some fantastic fuel economy you got there! Better than I've ever achieved with the inefficient old IDI.
Try running a rear sway bar only and no front sway bar. I've found the rear end is much looser on these than the front. I never run front sway bar anymore. Just rear if I'm towing, and nothing the rest of the time.
Fastest I've had my Prado is 150km/hr (GPS and speedo indicated) on 235/85R16 at 50psi with a 2" lift only and nothing on the roof. I was using meth/water injection to get the extra hp. It actually had a bit more in it. It can't go that fast anymore now that it's on 35" tires with a taller lift. About 130km/hr max now.
That is some fantastic fuel economy you got there! Better than I've ever achieved with the inefficient old IDI.
- Thread starter
- #339
I've been meaning to get the rear sway bar put back on but need to make 1/2" spacers for the brackets on the axle before I can do that; correcting the pinion angle caused interference between the sway bar and radius arm.
Good to know about the front sway bar, once I've got the rear back on I'll try pulling the front and see how it does. Some extra articulation would be nice.
Good to know about the front sway bar, once I've got the rear back on I'll try pulling the front and see how it does. Some extra articulation would be nice.
- Thread starter
- #340
Glad to know my tribulations can be of help to someone! In my case I had quite a few issues that contributed to the problem initially. My tires were out of balance, one u-joint had a stiff spot, driveline angles were messed up and the driveshaft was out of balance and not quite straight. Basically everything that could cause a vibration happened! Start with the easy stuff first: check your u-joints for endplay and pull the driveshaft out to check for stiff u-joints and make sure the slip joint is sliding smoothly. Take a drive with it out and see how it feels. Tires are easy to have checked for balance at a tire shop.
