This write-up details a front right DOJ boot replacement job.

Tools Required

• External snap ring pliers
• Torque wrench measuring up to 137 ft/lbs
• Impact gun (unless you enjoy removing strut bolts the hard way)
• 32mm socket (though not correct, I’ve used a 1 1/4″ socket without problems instead of a 32mm one)
• 19mm impact socket (short worked fine for me, deep would work better)
• 19mm wrench (or another 19mm socket and a ratchet)
• 12mm socket
• 3/16″ pin punch
• Hammer
• Beefy scissors or razor knife

Subaru Parts

Source grease (pre-measured amount when purchased from Subaru), an axle nut, an axle spring pin, a DOJ (inner) boot, and DOJ boot straps/clamps from a Subaru parts dealer.

Process

1. Break your lug nuts free (just barely) while the car is on the ground. DO NOT break your axle nut free yet.
2. Get the front of the car up on jack stands
3. If you examine your axle nut, you will see that it has been locked in place by indenting the nut into the keyed area of the axle itself. “Unlock” the axle nut with a hammer and cold chisel or similar so that the nut will eventually turn for removal.
4. Have someone apply heavy brake pedal pressure while you remove the axle nut with your 32mm socket. You will likely need a “cheater” bar to extend your breaker bar for much more torque in order to break the nut free. I had to use roughly 4ft of length to get mine to break free. Be careful to not scratch your body panels.
5. Discard the axle nut.
6. Remove your lug nuts and wheel
7. Remove the 12mm bolt holding your brake line to the strut
8. Using your impact gun and 19mm socket, disconnect the lower portion of the strut from the hub/knuckle assembly. Your strut should be free from the knuckle entirely, and easy to move. This lets you manipulate the hub/knuckle freely later in order to get the axle removed from it, but don’t do it yet.
9. Locate the spring pin that is through your axle near the transmission. Using a pin punch (not tapered!) and hammer, drive the spring pin out of the axle. Discard the spring pin.

 


10. You should be able to completely remove the axle from the transmission’s splined axle stub, then from the female-splined hub/knuckle assembly. I had to pursuade the axle out of the hub/knuckle by driving something appropriate against the end of the axle itself, sort of the same idea as used for the spring pin…
11. Sweet. An axle. Prepare to get really messy. I recommend several pairs of nitril or latex gloves and lots of paper towels.
12. Remove the bad boot’s retaining bands in whatever way you see fit. Discard them. Cut off the old torn boot in whatever way you see fit. Trash it.
13. Inside the DOJ housing (usually green), you will find a wire which prohibits the DOJ from coming out of the housing. If you can’t find it, wipe away more grease until you see it. Carefully spiral the wire out of the housing and set it aside. Do not bend it. I did this with my fingers and it was not difficult. You will be reusing this wire ring.
14. Remove the DOJ assembly from the green housing and set its 3 rings aside.
15. Wipe off the “top” of the DOJ “tree” (technically this is called the trunnion) and you will find a snap ring. Carefully emove this snap ring with your snap ring pliers, taking care not to lose an eye in the process. You can reuse this if you don’t mess up the snap ring.
16. With the snap ring removed, you can now slide the 3-nub head off of its splines to separate it from the axle.
17. You now have an axle with the DOJ end completely bare, a trunnion, the 3 rings that go onto the trunnion, a retaining wire, a snap ring (“circlip”) and the green housing.
     
    

    

18. If you’re keen to, wipe all of the grease off and clean the trunnion, the 3 rings, and the housing with degreaser until they’re spotless. My axle had about 20,000 miles on it, so I did not bother with this step. I just wiped some of the grease off so I could see what I was doing.
19. Install your new boot, small end first, onto the bare end of the axle and secure that end with your “small end” strap or clamp. My Subaru parts counter gave me some stainless steel zip-tie like things that I wasn’t crazy about, but I used them anyway.
20. Put the trunnion back on the axle splines and put the snap ring back in place to retain it
21. If your trunnion is cleaned off, spread some grease on the nubs
22. Place your 3 rings on your trunnion. They can only go on in 1 direction.
23. Fill the green housing half way with grease.
24. Insert the DOJ assembly into the housing, taking care not to knock off any of the 3 rings, and install the circular retaining wire so the DOJ can no longer come out of the housing.
25. Put the rest of your grease in the new boot
26. Slide the large end of the boot onto the housing and wipe off any major gobs of grease for the time-being.
27. Use your “large end” strap/clamp to secure the large end of the boot to the housing.
28. Clean up any remaining grease on the exterior of the axle.
29. Reinstall your axle, taking note to exactly line up the hole in the splined hub at the transmission to the hole in the end of the axle. This is where the spring pin will be reinstalled. It may take several tries to get installed on the correct spline.
30. Install a new spring pin through the axle. The spring pin is tapered a little on each end, so you can use your hand to push it in just enough so that it stays on its own. You do not have to hold it with one hand while you hammer it in with the other hand (like a nail). If you tap it in and it stops after 1/4″ or so, you do not have the holes lined up — do not proceed to hammer harder.
31. Reattach your strut to your hub/knuckle with the 2 bolts and impact socket (120 ft/lbs)
32. Install a new axle nut (never reuse old axle nuts!). Have someone stand on the brakes again and tighten to 137 ft/lbs. Make sure you do this with the car in the air still!
33. LOCK the axle nut with a hammer and something (I used a cold chisel)!
34. Reattach your brake line to the strut body.
35. Reinstall your wheel with lug nuts tightened by hand as tight as you can get them.
36. Lower the car to the ground
37. Tighten your lug nuts fully
38. Go for a short test drive around your area

“Thermography is the use of an infrared imaging and measurement camera to “see” and “measure” thermal energy emitted from an object. Thermal, or infrared energy, is light that is not visible because its wavelength is too long to be detected by the human eye; it’s the part of the electromagnetic spectrum that we perceive as heat. Unlike visible light, in the infrared world, everything with a temperature above absolute zero emits heat. Even very cold objects, like ice cubes, emit infrared. The higher the object’s temperature, the greater the IR radiation emitted. Infrared allows us to see what our eyes cannot. Infrared thermography cameras produce images of invisible infrared or “heat” radiation and provide precise non-contact temperature measurement capabilities.” Source: Flir.

Surely you’ve seen Predator, right? Infrared thermography is what the Predator used sometimes to detect Schwarzenegger and his gang in the dense jungle.

Basically it’s temperature-vision, and avoidable or excessive heat robs power.

Great, but the cameras are extremely expensive!

Yes, we know. Cool technology is often completely out of reach to purchase unless you have a hefty budget. This is one of those times where rental is going to have to be good enough and luckily there are plenty of inspection companies (among others) with IR cameras. If you perform a search for “property inspection thermal” along with your city and state you’re likely to get many results.

We hired a local property inspector who agreed to take pictures for $100. Ouch. Do you people see what we go through to make these articles even when we’re far from making our first cent of profit yet? Fine, enough of the sob story. By the way, if you just want to rent a camera and figure out how to use it on your own, you can.

Also, a quick note about the cameras: They’re typically far lower resolution than even your typical consumer digital camera. I think the cameras have just started hitting the 2 megapixel range, which is equivalent to digital cameras from about 1997. The pictures taken by our hired help are only 240×240 in original format (and his camera cost $8000!). They have been resized to 480×480 below.

What’s to gain?

With careful examination of your images you should be able to determine problematic areas and develop a plan toward improving them. Perhaps you’ll find that your intake manifold is absorbing too much heat from your cylinder heads. Maybe you’ll find that something is generating far more heat than you imagined possible. Most batteries are known to work poorly in extreme heat. Is your battery absorbing excessive heat due to its position in the engine bay? Are your brake lines properly shielded from the extreme temperatures generated under hard braking? Is your turbocharger completely roasting things nearby? There are hundreds of reasons for this sort of heat analysis.

Images

First we have a head-on shot of the engine bay. The nasty hot spot in the upper left of the image (pinkish white) is a coolant reservoir. Just above and to the right of that you should be able to make out a fairly large pipe with a curve to it. The top of the pipe shows as light blue, the middle portion shows as dark blue, and the bottom appears to be much hotter. How is it possible that a pipe is only hot on the bottom when we all know heat propagates through materials? It turns out that reflective materials and IR thermography don’t play well together. The bogus hot spot you are seeing is actually the portion of the pipe that happens to be reflecting directly back into the camera. More proof and commenting on this with later images. For reference, the single dark blue dot in the middle bottom of the image is where a radiator hose connects to the aluminum radiator (you can see the roughly 170F orange-colored hose if you look closely). The radiator runs left to right and is green, yellow, and blue – colors which do not accurately represent the true temperature.

Below, another view similar to the one above. Take note that the color to temperature mapping legend at the bottom has changed. This is true for each individual image based on the range of temperatures in the entire image. The dark red area just to the left of the camera’s black targeting crosshair (in the center) is the alternator.

The following 302F hot spot is the SwainTech “White Lightning” coated up-pipe to the turbocharger’s exhaust housing. It is actually quite a bit deeper into the engine than the image represents.

Although the car had been sitting for 15 minutes when the following picture was taken, it’s a pretty neat shot showing the actual cooling process, right to left, of the front mount intercooler.

This shot of the front wheel is curious because it shows the disc of the 2-piece rotor itself quite cool (around 100F, blue), the “hat” of the 2-piece rotor at around 126F (almost white), and the spokes of the rim (red) have absorbed quite a bit of the heat that was transferred from the “hat”. The yellowish green slots in the rotor also indicate that they cool more slowly than the exterior surfaces of the rotor (blue).

Once again, proof that reflective surfaces are troublesome to image properly with IR. This side image shows the top of the aluminum radiator (dark blue and to the left of the crosshair) as a cozy 85F. I don’t recommend putting your hand on it to test the accuracy of the IR camera. It’s actually about 220F in this image.

While these specific images may not mean a lot without having the physical engine bay in front of you like we have, hopefully you can gather the importance of this sort of study. If you have any questions or comments, please feel free to speak your mind below. Happy heat hunting. ∞

While looking for some heat shielding to add to the pieces already in use, I started considering the bang-for-buck factor of the various products on the market. Previously, I’d just ordered DEI products for no real reason other than familiarity with the brand name. It occurred to me that although all of the manufacturers’ products in this arena seemed to be made of extremely similar material, maybe one of them worked better than the others.

After a few rounds of email to ThermoTec and Heatshield Products (a new name to me, but they’ve been around a long time), I had some similar products in hand to put through some testing. I already had some of DEI’s product to use.

The Combatants

For the testing, I stuck to one category of heat shielding product: sleeving / sheathing.

DEI Heat Sheath

“Heat Sheath is made from a Hi-Temp fiberglass fabric bonded to an aluminized material then sewn into a tube. Designed to slide over wires and hoses this product can be easily shaped to fit the tightest bends. The Heat Sheath will reflect up to 90% of the radiant heat and can insulate against up to 500 degrees direct continuous heat. Easily cut to length with scissors or a sharp knife.”

ThermoTec Express Sleeve

“Thermo-Tec’s new Express Sleeves are just exactly what our customers have been looking for. The new easy to use sleeving is a combination of a high temperature insulation material to a highly reflective mylar foil with a Velcro closure. The sleeving is designed to provide maximum protection for wires, hoses, and cables from the very damaging effect of radiant heat with an easy application. Simply pull apart the material, wrap around the wire, and re-close the sleeving. Express Sleeves reflect over 90% of radiant heat, is fireproof and fire resistant, and just looks good.”

Heatshield Products Reflect-A-Sleeve

“Keep your wiring, fuel lines, brake lines, and cables safe from heat damage. Our heat resistant hook and loop seam makes installation easy. No disassembly required. Trying to protect your wires? Use our sleeve as a high temperature heat resistant wire loom! Use it as a shield for your intercooler or air intake pipes. Reflect-A-Sleeve acts as a thermal barrier capable of reflecting up to 95% of radiant heat away. *Weight*[sic] there is more, a 3′ length our Reflect-A-Sleeve weighs less than 6″ of the old silicone covered stuff. Though it weighs much less, it offers superior heat shield protection. Reflect-A-Sleeve withstands 1100°F continuous of radiant heat and 500°F direct heat. ”

I recently had the pleasure of replacing my throttle body. In the process, I learned plenty about the setup that I can share with you.

Disclaimer: I can only confirm these instructions and torque specs for the 2002-2004 non-STI WRX models. Using these instructions on any other model could be problematic. For instance, I know for sure that the 2004+ STI torque spec for the 4 TB mounting bolts is 1/4th of what it is for the WRX.

The Pieces

• A – Idle Air Control solenoid valve and gasket directly on top of main chamber (2 screws)
• B – MAP sensor located on the top left (2 screws)
• C – Throttle Position Sensor located low on the driver’s side (2 screws)
• D – Coolant line attached to driver’s side with spring-loaded hose clamp
• E – Coolant line attached to bottom side with spring-loaded hose clamp
• F – Throttle body to intercooler hose (2 hose clamps)
• G – Gasket between throttle body and intake manifold

Removal

NOTE: Before you remove anything, it is recommended by Subaru that you prepare to use a replacement gasket for the throttle body.

NOTE: If you remove the Idle Air Control solenoid valve from the top of the throttle body, replace the rubber gasket inside. I didn’t, and sucked quite a bit of coolant into my engine before I wised up — not good.

NOTE: During this job, I tore the heads of two sensor screws due to the force needed to break them free from their factory over-tightened state! Be prepared for some trouble. I ended up having to ride my bike to True Value to find replacements.

Tools needed: 1 rag, pliers, socket wrench, 12mm deep socket, large flat-head screwdriver, 10mm short socket or preferably a 10mm GearWrench (for the 3 breather line screws in the front of the intercooler)

1. Let the engine cool. Your coolant should be cool/warm and no longer under pressure.
2. Remove the intercooler and thoroughly clean the bolts (they will be used in a bit to plug the TB coolant lines)
3. Remove the intercooler-to-TB hose and hose clamps
4. Unplug all 3 sensors (A, B, C)
5. Disconnect the throttle and cruise cables by pulling each spring-loaded assembly toward the front of the car, then pushing the small cylinder at the end of the cable out of its housing. You should see what I am talking about. It is not difficult, and is just like a bicycle’s brake cable set up. Holding the spring-loaded housings for 10-20 seconds while you unlatch the cable can start to become…uncomfortable. You might want to put a work glove on your pulling hand.
6. Using pliers, compress the coolant line hose clamps and slide them down each respective hose about 2-3 inches. Don’t worry, the hose shouldn’t pop off the TB without effort.
7. Now, one by one, remove the 2 coolant lines from the TB. Plug the ends of the hoses with your clean intercooler bolts. Use your rag to dab up any coolant that may have dribbled around – no big deal.
8. Unbolt the 4 bolts holding the TB to the intake manifold
9. Set the TB aside and remove the TB-to-manifold gasket
10. If you’re going to have the TB off for more than 10 minutes or so, I highly recommend finding a very clean rag to stuff in the intake manifold opening. Better safe than sorry.

Installation

Reverse the order of removal, but be very careful not to overtighten any bolts. The torque specifications are as follows:

1. 4 bolts holding TB to intake manifold = 15.9 ft/lb (22 N-m)
2. MAP sensor screws = 1.2 ft/lb
3. Idle Air Control solenoid valve screws = 2.1 ft/lb
4. Throttle Position sensor screws = 2.1 ft/lb

You may need to bleed your coolant system afterward (unlikely).