Builds Another Prado in Montana (1 Viewer)

[AirheadNut]

A few more random observations:

I’m running Cooper Discoverer S/T Maxx tires, and love them so far. Great traction in the snow, and quiet on the highway.

The engine builds up to 5psi boost when coasting, it must be the way the VNT turbo is set up and programmed in the ECU. This means that it has much better engine braking than a 1.9L should in this heavy of a vehicle.

The engine warms up quickly, but runs relatively cool. The heater will be blasting hot air within a couple of miles of driving, but the radiator will still be cold 15 minutes later. In winter conditions the thermostat hardly has to open when driving around town.

Still chasing the vibration/steering shimmy. The front wheel bearings need to be repacked and tightened up, which will hopefully cure the 100km/h wobble. I have a spare tire on order, and when it arrives I’ll have the tire shop rebalance all the tires and see if that cures the vibration that starts at 80km/h. I confirmed the E-hubs were working properly, and did 110km/h today in 4wd. If anything there is less vibration in 4H than 2H.

Loving every minute of driving it, despite the few quirks!

 

[AirheadNut]

2nd fuel up, 1/2 with RTT, 1/2 without.

 

[AirheadNut]

A Stage 4 tune is officially in the works! Another set of injectors has been sourced and will be shipped off to have Bosio 1019 nozzles installed and calibrated, and the tuning company has been contacted. Looking forward to an additional 45hp and 85lb-ft of torque, should make quite a difference!

 

[JimmyPrado]

A Stage 4 tune is officially in the works! Another set of injectors has been sourced and will be shipped off to have Bosio 1019 nozzles installed and calibrated, and the tuning company has been contacted. Looking forward to an additional 45hp and 85lb-ft of torque, should make quite a difference!

That should definitely make your rig officially a VWJ78.

 

[AirheadNut]

I've been thinking more along the lines of ALHJ78, though it is quite a mouthful. Dug these out of the back corner of a box this evening, I need to spruce them up a little and figure out where to stick them on.

 

[AirheadNut]

Well, I did some more diagnostic work trying to figure out the driveline vibration I'm having; it has gotten a lot worse during the last couple of days. With the vehicle up on the lift I put the transmission and transfer case both in neutral and started spinning the wheels and driveshafts and listening for any odd noises. The u-joints and slip joints all feel tight, but I did give them a couple of pumps of grease each. Both pinions feel good, as do the transfer case outputs. There is a slight clicking noise coming from each of the rear hubs, I'm pretty sure it is rear wheel bearings. Some time ago I ordered all the gaskets, o-rings and oil seals for the rear axle, but didn't get new bearings, so a Partsouq order is in the works.

I also found some play in the front wheel bearings, so I need to take the hubs apart and repack the bearings. Any tips on disassembling the electric hubs? Do I need to get new hub gaskets or cone washers, or can I reuse the old ones?

Unfortunately, I have to leave for school again before the parts arrive, so it may be a few weeks before I can get the Prado back on the road. On the bright side, by then everything should be in place for the Stage 4 tune...

 

[GTSSportCoupe]

Well, I did some more diagnostic work trying to figure out the driveline vibration I'm having; it has gotten a lot worse during the last couple of days. With the vehicle up on the lift I put the transmission and transfer case both in neutral and started spinning the wheels and driveshafts and listening for any odd noises. The u-joints and slip joints all feel tight, but I did give them a couple of pumps of grease each. Both pinions feel good, as do the transfer case outputs. There is a slight clicking noise coming from each of the rear hubs, I'm pretty sure it is rear wheel bearings. Some time ago I ordered all the gaskets, o-rings and oil seals for the rear axle, but didn't get new bearings, so a Partsouq order is in the works.

I also found some play in the front wheel bearings, so I need to take the hubs apart and repack the bearings. Any tips on disassembling the electric hubs? Do I need to get new hub gaskets or cone washers, or can I reuse the old ones?

Unfortunately, I have to leave for school again before the parts arrive, so it may be a few weeks before I can get the Prado back on the road. On the bright side, by then everything should be in place for the Stage 4 tune...

Interesting about the rear axle bearings. How many kms on your truck again? I've heard normally these bearings go a very long time. Maybe oil level was low at one point and caused some damage? In any case, please take lots of pictures when you do this job. I'm very curious to see how things look in there. I'd be interested to know axle shaft diameter, and see how big the bearing is etc. So many people think the rear axles on these are in-superior even to semi-floating HD models; but I beg to differ. I've actually never heard of one in a 1990+ LJ7x or KZJ7x having a major failure. Diff yes, but not axles/bearings. Is it possible the noise you're hearing is from the e-brake shoes inside?

I always struggled with play in my front wheel bearings too - until I went to manual hubs. The e-hub design does not lend it's self to proper bearing pre-load adjustment. Try to find manual hub parts if you can - I think it's one of the best upgrades for these trucks. You just need spindle/hub/freewheel assembly along with the hardware. Re-use the bearings they come with if they're good, or buy a new bearing set. You wouldn't regret it. You can get the parts from any 1978+ 40/60/70 series or solid axle 'mini truck'/ 4runner. Pre '78 40 series works ok too, but the rotor is different in that it bolts onto the hub instead of presses on. Still works fine with the LJ78 calipers though. Also the hubs are Warn and too long, so you will still need to find Aisin hubs. This is actually the way I went - my parts are from a '76 40 series. To be honest, I really like the bolt on rotors better, as they are way easier to replace now. Here are some pictures from when I did this a year ago: LJ78 Elec to Manual Hub - https://photos.app.goo.gl/9GXrrVhEwrsU5wuh7

Anyhow, if you stick with the e-hubs, just use the RM183e manual to disassemble and reassemble. There are two versions of that manual. One version has the e-hub section, the other has it missing. You can re-use all the hardware, but should buy new gaskets.

What are you taking at school outta curiosity?

 

[AirheadNut]

Well, I had the new spare tire put on today, and all the others rebalanced. The vibrations at speed have drastically decreased, including the front wheel shimmy, so I think that was a large part of my problem. There is still a slight growl coming from the rear of the vehicle over 80km/h, so I think I'll drain the rear diff and see what the fluid looks like. The e-brake is definitely out of adjustment since I replaced the rotors and calipers, so that may be what I'm hearing. The truck only shows 115k kms on the odometer, so failed wheel bearings would have to be due to low fluid or water intrusion. It will be nice to have more than 4 inches of exhaust pipe off the back of the turbo, I'll actually be able to hear the other noises when driving!

The new spare tire is just a hair too large to fit on the tire carrier, so it will have to be modified. I tried flipping the carrier, but had issues with the rear window wiper interfering with both the tire carrier and the tire.

@GTSSportCoupe I'm working on finishing a long-overdue mechanical engineering degree.

 

[GTSSportCoupe]

Well, I had the new spare tire put on today, and all the others rebalanced. The vibrations at speed have drastically decreased, including the front wheel shimmy, so I think that was a large part of my problem. There is still a slight growl coming from the rear of the vehicle over 80km/h, so I think I'll drain the rear diff and see what the fluid looks like. The e-brake is definitely out of adjustment since I replaced the rotors and calipers, so that may be what I'm hearing. The truck only shows 115k kms on the odometer, so failed wheel bearings would have to be due to low fluid or water intrusion. It will be nice to have more than 4 inches of exhaust pipe off the back of the turbo, I'll actually be able to hear the other noises when driving!

The new spare tire is just a hair too large to fit on the tire carrier, so it will have to be modified. I tried flipping the carrier, but had issues with the rear window wiper interfering with both the tire carrier and the tire.

@GTSSportCoupe I'm working on finishing a long-overdue mechanical engineering degree.

@AirheadNut , I was able to fit a 35x12.5R15 on 15x8 -27mm rim on my spare tire carrier by: A. Flipping carrier as you have B. Installing a 1.25" wheel spacer. The wheel spacer made the tire clear the wiper back to stock clearance. My left door just grazes the tire when I open it. The tire clears the bumper by 1/8" or so. A larger tire would need a custom (or re-drilled) carrier. Pictures here: TOYOTA PIC OF THE DAY POST - https://forum.ih8mud.com/threads/toyota-pic-of-the-day-post.864218/post-13330974

You could probably get away with a thinner wheel spacer.... If you find one cheap, it's an easy way to go. Not requiring any fab.

Mechanical Engineering seems about perfect for you from what I can tell, haha.

 

[AirheadNut]

@AirheadNut , I was able to fit a 35x12.5R15 on 15x8 -27mm rim on my spare tire carrier by: A. Flipping carrier as you have B. Installing a 1.25" wheel spacer. The wheel spacer made the tire clear the wiper back to stock clearance. My left door just grazes the tire when I open it. The tire clears the bumper by 1/8" or so. A larger tire would need a custom (or re-drilled) carrier. Pictures here: TOYOTA PIC OF THE DAY POST - https://forum.ih8mud.com/threads/toyota-pic-of-the-day-post.864218/post-13330974

You could probably get away with a thinner wheel spacer.... If you find one cheap, it's an easy way to go. Not requiring any fab.

Mechanical Engineering seems about perfect for you from what I can tell, haha.

Good to know! I'll have to keep an eye out for a used spacer.

I did some more driving and careful listening and am not so sure my earlier diagnosis of wheel bearings is correct. Now that the tires are properly balanced there is a lot less noise and vibration, but the rumble starting at 80km/h is still there. Under acceleration and coasting it isn't too bad, but when I lift off the throttle slightly and unload the drivetrain it gets a lot worse. To me it sounds almost exactly like when I had a u-joint fail in my G-Wagen a few years ago, just not as bad. Could a slightly worn u-joint cause a vibration without showing any signs of play? My other thought would be pinion or carrier bearings, but it seems like they would make more noise under heavy load, rather than the other way around.

Looking at the parts diagrams, it appears that all four u-joints (front and rear driveshafts) are the same, but currently my front u-joints are non-greaseable and the rears have a grease fitting. Even with the shipping, the u-joints are cheaper from Partsouq than I can get them locally, so I think I'll start by replacing the two in the rear driveshaft and see if that makes any difference. I'd rather not tear into the rear diff or axle if I don't have to.

 

[malteser]

Could a slightly worn u-joint cause a vibration without showing any signs of play?

Last u-joint I changed showed no signs of play but was seized on one axis (was a sealed, non greasable type). It made strange squeaking noises and vibrations.

 

[AirheadNut]

Another bit of maintenance I forgot to post: I replaced the front shocks a few weeks back. Initially I tried to do it sans spring compressor like @GTSSportCoupe suggested in another thread by loosening the control arm bushings on the frame and dropping the front axle down, but the factory brake line running from the frame to the axle was just a little too short and wouldn't let the axle drop far enough. With an extended brake line that would be a really quick process. I was in the middle of replacing the struts on my Jetta so I already had a spring compressor rented.

 

[malteser]

Another bit of maintenance I forgot to post: I replaced the front shocks a few weeks back. Initially I tried to do it sans spring compressor like @GTSSportCoupe suggested in another thread by loosening the control arm bushings on the frame and dropping the front axle down, but the factory brake line running from the frame to the axle was just a little too short and wouldn't let the axle drop far enough. With an extended brake line that would be a really quick process. I was in the middle of replacing the struts on my Jetta so I already had a spring compressor rented.View attachment 2550584

A good technique I use for front springs is car on the ground, trolley jack from axle side I want to work on (lift wheel couple inches off the ground), put jack stand under chassis just behind control arm, remove wheel, undo sway bay from axle, undo shock, lower jack and let axle articulate until spring is free. You might even need to push down on the hub to articulate more, depending on lift.

 

[GTSSportCoupe]

A good technique I use for front springs is car on the ground, trolley jack from axle side I want to work on (lift wheel couple inches off the ground), put jack stand under chassis just behind control arm, remove wheel, undo sway bay from axle, undo shock, lower jack and let axle articulate until spring is free. You might even need to push down on the hub to articulate more, depending on lift.

I was trying to figure out why my method was not working for @AirheadNut and you nailed it. I see now he lifted the whole front end. Like you @malteser , I just did one side at a time. I still have OEM length brake lines, so was trying to figure out what the difference was, as the length wasn't a limiting issue for me. That said, I do really need to install longer ones sooner than later.

 

[AirheadNut]

Got a call this morning that the exhaust shop finally had an opening! Since I'm currently 300 miles away, @SnowVersion kindly dropped the Prado off. Can't wait to hear what it's like with a side pipe!

 

[SnowVersion]

@AirheadNut has been working on his Prado build in my shop for the past 3 years, but it seems like more often than not, I hear about his progress on mud. So I decided that I’d post this here instead of telling him directly.

Side exit exhaust!

It’s a 2.25” downpipe down to the bottom of the fender and then a 2.5” straight pipe the rest of the way.

3000 rpm shifts under load yield glorious turbo whistle. I seriously wish my 1hdt sounded this good!

 

[AirheadNut]

Looks great! I can’t wait to take it for a test drive. Hopefully the new u-joints fix the vibration problem this weekend and it can assume daily driver status.

 

[fordyota]

Another bit of maintenance I forgot to post: I replaced the front shocks a few weeks back. Initially I tried to do it sans spring compressor like @GTSSportCoupe suggested in another thread by loosening the control arm bushings on the frame and dropping the front axle down, but the factory brake line running from the frame to the axle was just a little too short and wouldn't let the axle drop far enough. With an extended brake line that would be a really quick process. I was in the middle of replacing the struts on my Jetta so I already had a spring compressor rented.View attachment 2550584

Just curious what springs you went with for replacement? Need to do same to my Prado and I am in info gathering mode.

 

[AirheadNut]

I am still running the stock springs, when the budget allows I’ll look into getting a 2” lift. The shocks I used are the Old Man Emu Nitrochargers, I got them from Dave at https://back40imports.com/

 

[AirheadNut]

Today I gained some confidence in my handiwork, driving 480km and crossing the Continental Divide. The Prado did great, cruising at 110km/h with the rooftop tent and a pile of luggage in the back. EGT's are a little higher with the exhaust on, but still nothing to worry about. Cruising on flat ground it ran 850-900ºF, and pulling hills rarely put it over 1150ºF. Going up the 8% grade over the Divide I ran at 80km/h in 4th gear and didn't get over 1050ºF. I drove the same pass 4 years ago in my previous Prado with 3 passengers and a bunch of camping gear and was reduced to driving 50km/h with my flashers on. My only concern is that coolant temps seem a little high. It may be because my temperature probe is right where the coolant exits the cylinder head. As much as I love them, I think the IPF Super Rally lights block a lot of airflow to the radiator, too. I have a few loose ends to wrap up, but now that the Prado has taken over daily driver duties I think the "swap" portion of this thread is officially over!