Toyota IFS Idler Arm Upgrades

4Crawler Offroad Products

Idler Arm/Bushing Upgrade

for 1986-1995 4WD 4Runner, Pickup, Hilux, Hilux Surf models

also fits T-100 pickup models

a product of Visual Diagnostics LLC

Contents:

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Introduction:

Check out our new YouTube videos on the idler arm upgrade:

If there was a "weak link" in the Toyota IFS Hilux pickups, 4Runners, and T100s, that would be the steering system. You can see below that it is a fairly complicated system with lots of moving parts and joints. One of the most highly loaded components in that system is the idler arm and it's operation is described in the paragraph following. Folks often ask if cranking up torsion bars or installing ball joint spacers or adding this or that sort of lift will cause increased wear and tear on the steering and idler arm. Actually the short answer is not really, but the longer answer is it depends. One likely reason for installing the lift is that you may be considering taller and/or wider wheels and tires. And you may be considering the lift and larger tires in order to either go off-road or to handle more challenging off-road driving. And with the lift and larger tires and harder off-road driving you may end up doing, that will put more wear and tear on the steering. So did the lift cause the steering wear or not?

A typical Toyota 4WD IFS steering system is pictured below. The steering wheel and shaft connect to the steering box (8). The pitman arm (9) connects to the sector shaft (10) on the bottom of the steering box and transfers steering input to the center link or relay rod (6). The relay rod connects to the idler arm (3) on the passenger side. To the ends of the center link are tie rod ends (2 and 4/5) that connect to the steering knuckles on each side of the front axle to turn the wheels. A steering stabilizer (7) attaches between the frame and center link to dampen jolts from the road. Of all these parts, only the idler arm and steering box are re-buildable, but the idler arm seems to take the brunt of the abuse and is the most common part to require repair.

If you are tired of destroying stock plastic idler arm bushings, these bronze bushings are machined to exacting tolerances in order to provide maximum strength and life. They are very hard and durable. As a result, not only can they bear much more load and resist wear, but they also transmit much less shock to the steering wheel making the truck easier to handle on rough roads.

One way to look at the purpose of the bushings on the idler arm is to imagine holding up a flag on a pole. If you only use one hand to hold the flag pole, it puts a lot of stress on that one hand and it is hard to hold it straight. If you use two hands separated by a distance, the load is more equal between your two hands and you can hold it straight a lot easier. WIth the stock plastic bushings, you have the idler arm set up more like the one-handed setup, since the bottom bushing can give under load letting the idler arm twist inside the housing. Now with the two bronze bushings, the shaft is held solidly and the forces are transferred along the shaft to both bushings more equally. Now there is a limit to the ultimate bending strength of the steel shaft and if you put enough load on it, it'll bend no matter what sort of bushings you use. The bigger the shaft, the stronger it is, given similar material. So the bushings are designed to fit the largest diameter shaft available in aftermarket idler arms.

One consideration of a machined bronze bushing is the need for tight tolerances in order to fit over the shaft of the idler arm and inside the housing of the idler arm bracket. Unlike soft plastic that can be squished into a too-small hole, the bronze bushings require a precisely sized hole and shaft for a good fit. We measured numerous idler arms in search of the strongest and most affordable to support. Luckily for you, we found both in some commonly available idler arms:.

Frequently Asked Questions:

  1. Why just support those idler arms?
  2. Do these bushings work with the OEM/factory Toyota idler arm?
  3. What do I do if I bend/break my idler arm?
  4. Do I need a zerk fitting in my idler arm with the bronze bushings?
  5. How will my order be shipped and how long will it take to arrive?
  6. What options are available for right hand drive (RHD) applications?

Any other questions not covered here, send us an e-mail

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Why just support those idler arms?

Good question! There are two main reasons but before getting into them it is important to point out that 1st and 2nd gen idler arms are interchangeable. The second gen arms are typically stronger though. Therefore, if you have a 1st gen truck, it make sense to install a 2nd gen arm for the added strength.

First, for the most strength, the largest shaft diameter is the key factor. Initially we assumed that we would want to at the very least produce idler arm bushings for the high-end Napa arm as well as the OEM arm because we assumed they would be the best. After an idler arm spending spree we found some interesting things we'll discuss below.

Idler Arm Model Shaft Dia.(in) Shaft Dia.(mm) Supported
McQuay-Norris FA5040 0.786 20.0/TD> Some *
McQuay-Norris FA5040GL
for Right Hand Drive		 0.786 20.0 Some*
Duralast FA5040 (original version) 0.786 (some) 20.0 Some *
Napa - Altrom/Ultra-8 ATM-1032403 0.786 (some) 20.0 Some *
Pro-Forged 102-10045 0.786/0.709 20.0/18.0 Some**
Pro-Forged 102-10052 0.786 20.0 Yes**
Duralast FA1739 0.786/varies 20.0/varies Some
Moog K80536 0.767 19.5 No
Napa - NCP2683702 0.767 19.5 No
Beck Arnley 1014228 0.767 19.5 No
Dealer/OEM 0.767 19.5 No
Sankei 555 0.767 ? 19.5 No *
Napa - ATM-1032403 (sold for 2WD & 4WD) 0.703 17.9 No *

As you can see, the arms with the largest shaft diameter are at the top of the chart. And that larger diameter equates to almost 11% increase in stiffness over the OEM part, since the torsional stiffness increases by the 4th power of the diameter. Another interesting note is that the Napa 1032403 which has a diameter similar to a 2WD OEM arm is also sold for 4WD trucks even though from a strength standpoint, this arm is below spec., in fact it is about 25% weaker than the FA5040 arm.

We also wanted to support shafts with high manufacturing quality, such factors as fully machined surfaces. Some of the shafts are only partially machined. A stretchy plastic bushing can be jammed in place with no problem, but this makes fitting a rigid bronze bushing impossible. The part of the shaft closest to the arm itself wears more than the rest. This means that a bushing that fits snuggly over the lower part of the shaft will not fit at all over the rest of the shaft. Assuming one was to verify that the shaft has a uniform diameter, there is the issue of calibration. My calipers might not measure out like yours. As a result it is difficult to machine the parts to order due to the tight tolerances in this application. To reduce part cost it is necessary to produce many at once and supporting one arm helps us accomplish this goal.

Given these issues we have decided to support the most affordable yet strongest idler arms.

NOTES:

(*) One thing to beware of is that sometimes, you'll get an arm in a box marked "FA5040" but be sure to check for a genuine FA5040 arm before taking the box out of the store. The genuine item is marked with a single "L", as noted below. The genuine arm is also in a nice shiny black clean finish. The imitation "iak9424" arms are in a rough dark gray finish, like they were taken directly out of the sand mold and into the box.

If you see a "555" stamped on the idle arm itself (click here for a picture of the stamping), that is likely a Sankei 555 arm, which is actually a smaller 2WD arm. If you find a "555" stamp, take that arm back and swap it for a genuine FA5040 arm. And you might want to be wary of on-line sellers, like on eBay, as you'll not be able to inspect the arm until it is shipped to you. If it is the incorrect part. you may be stuck with shipping it back for an exchange.

Also, some Duralast FA5040 arms have a casting mark of "iak9424 L (click for picture of stamping)" instead of the plain "L" on the genuine FA5040 arm (click for picture of genuine FA5040 arm). The Pro-Forged arm also has "YN130" stamped onto the top of the forged arm section. This "iak9424 L" arm has an undersized shaft, comparable in diameter to the 2WD arm and appears to be a lower quality part. So be sure to check for that when you get the arm. Best bet is to pick one up at your local FLAPS where you can open the box at the counter and verify you are getting the genuine article before leaving the store. Note that some parts catalogs list a Duralast FA1739 arm for certain model years. This arm while the same overall mounting dimensions as the FA5040 arm, has a lower quality casting and the arm shaft diameter is poorly machined meaning that it is difficult to get the bronze bushings onto it. So ignore the parts catalog recommendation and go with the FA5040 part. And this also applies to the Napa-ATM-103-2403 idler arm, if it has just the "L" casting mark, then it is likely the "good" version, otherwise, it is likely a version with a different diameter shaft. THe only way to know for sure is to remove the shaft and measure the diameter.

(**) The Pro-Forged idler arms generally have the larger 20mm dia. shaft, this is a good thing. We have seen some recent 102-0045 idler arms that have a crudely cast "L" in the housing plus a hole for a grease fitting and gray plastic bushings. Unfortunately, these models seem to have an 18mm dia. shaft vs. the 20mm shaft that the original 102-0045 arms had, so be sure to open up the arm to check the shaft diameter. There are also new versions with an upside down "L" and a grease fitting hole that do have a 20mm shaft. Here's a photo of the two

The shafts on the ProForged arms are made of heat treated 4140 Cro-Moly steel for added strength. However, the inner diameter (ID) of the bushing seats in the "L" cast housing is a bit smaller than the FA5040 arm. Two options are to use a Dremel with a sanding drum or grinder wheel to remove a few thousandths of an inch from inside the housing until you can fit the bushing in place. Or we can custom machine the bronze bushings to fit that housing for an additional cost. See below for ordering options on bushings and idler arm kits. Now there also appears to be a new model of this arm that lacks the "L" in the casting, but instead has a threaded hole for a grease fitting where the "L" used to be. This arm housing has the same bushing seat ID at the original FA5040 arm and thus will accept the regular bronze bushings, although you may need to do a little touch up sanding on the ID of the arm housing to clean up any burrs. So you can order those or you can order our "Pro-Forged" bushing kit and specify you want the full size bushings and we'll add in a grease fitting that fits the hole in the arm housing. Or if you order one of our Pro-Forged arms, we'll make sure there's a grease fitting, which Pro-Forged sometimes omits. Unfortunately we can't guarantee which arm you'll get as they both have identical part numbers and what shows up in our latest shgipment is what we have to work with. If ordering a Pro-Forged arm from another supplier, best advice is to wait until you have it and then see if you have the "L" casting or the grease fitting hole before ordering bronze bushings. We are simply reporting the findings of our product research and trying to pass that on to our customers. Pro-Forged also lists a 102-0052 model arm for some model year trucks. That arm seems to be almost the same as the 102-0045 arm and the Pro-Forged bushings fit just fine. There seems to be a slight length difference in the arms, with the later model year trucks having a slightly longer pitman arm that should match the slightly longer idler arm. That said, both idler arms will work with either the earlier or later model trucks / steering boxes / pitman arms, match them up if you want. Again, there seems to be 2 versions of both these models, one with the "L" on the outside of the housing and the other with the grease fitting hole on the outside and a faint "L" on the inside face of the casting.

The bushings are built with an inside diameter (ID) of approx. 0.787" (20mm) and an outside diameter (OD) of 0.941" (~23.9mm) to fit over the idler arm shaft and inside the idler arm housing. The acid test is to measure the diameter of the shaft inside the idler arm, and you need to take it apart to do that. If you lack a micrometer or calipers to do that, wrap a piece of paper or masking tape around the shaft then slice that where it overlaps. Take that paper or tape off and measure the length, a 20mm shaft will measure just short of 63mm long, a 19.5mm shaft will measure just over 61mm long. You really can't tell from the outside of the arm what the inner shaft dimensions are. Why is that? Because all the aftermarket parts mfgs. have to more or less copy the OEM design as far as the bolt flange, angle, height and rough overall dimensions of the arm housing, because it needs to be a direct bolt-in replacement for the OEM arm. The only thing they can change are what's inside. Some mfgs. seem to "cheap" out and throw in a 19mm shaft with some thick bushings, others copy the OEM arm and use 19.5mm shaft and bushings. And finally a few mfgs. go up a size and use the 20mm shaft and bushings. As the saying goes, "you can't judge a book by it's cover".

Now if you are stuck with an idler arm with the smaller 19.5mm diameter shaft and want to use the idler arm bushings, there is an option. You can obtain some brass shim stock of the appropriate thickness to make up the different in diameter between the shaft and bushing. We can supply such shim stock if desired. It can also be ordered with the bushings if you are unable to check the size of your idler arm shaft prior to ordering. The piece of bushing stock will be cut to ~60mm wide to roll into a ~20mm dia. circle and will be approx. 6" / 150mm wide to allow it to be trimmed down (with scissors) to just fit from the top to the bottom of the idler arm housing. This way the coiled up shim stock will sit inside the housing and bushings and the shaft will fit down inside that shim stock. This should allow most of the 0.767" / 19.5mm idler arm shafts to fit. You may need to do some light filing/sanding of the housing to fit the OD of the bushings if needed. We can supply either 0.009" or 0.004" shim material. The 0.009" shim will make up the 0.5mm difference in one layer, the 0.004" will include enough material for 2 layers, giving flexibility to handle shafts slightly over 19.5mm. Either piece of shim stock is US$10.00 plus postage or $9.00 additonal when ordered with the bushings, specify your thickness preference in the Special Instructions to Seller section of the order form.

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Do these bushings work with the OEM/factory Toyota idler arm?

As described above, no, not directly. This is one of those "rare" cases where the aftermarket parts are actually better than what the factory put on the truck. In idler arms, "bigger is better" and the aftermarket idler arm shafts are a bigger diameter than the OEM part, plain and simple. So if you have a factory arm and the plastic bushings are shot, your two choices are to pick up a replacement plastic bushing kit at the dealer or pick up one of the larger after market idler arms (above). Or we do offer a brass shim kit that you can use to wrap around your undersized OEM arm shaft to fit inside the bronze bushings.

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What do I do if I bend/break my idler arm?

4Crawler Offroad does not warranty bushings damaged by bent idler arms. However, not to worry. If you bend an idler shaft and damage the flange of one of the bearings, you can simply remove the bushings reverse them placing the damaged flange bushing on top with flange loads are very small. If you bend another, rotate the bushing 180 degrees. At this point, if you bend another, you will need to purchase a new pair of bushings. The good news is that hopefully your idler arm has been covered under warranty by your local auto parts store. Unfortunately, our idler arm supplier doesn't offer a warranty on the arms we re-sell. So if you can find an arm with a better warranty, by all means get that one and get the bushings from us.

Here's some Amazon links if you want to go that way, by all means, go ahead. If you use one of our affiliate links below, we earn a small commision
ProForged 102-10045
ProForged 102-10052

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Do I need a zerk fitting in my idler arm with the bronze bushings?

Not required, the bronze bushings are self-lubricating. Grease will not hurt them so there is no need to wipe clean grease off of the housing and/or shaft but there is no need to install a zerk fitting if the idler arm does not have one. Bronze is slightly porous and will absorb oil from the grease and then slowly release that oil over time as the shaft moves inside the bushings. If there is a grease zerk, by all means you can use it to add grease as needed. If you have the tools, it's easy enough to drill a pilot hole in the outside of the arm bracket and then thread it for a fitting. The Pro-Forged arms tend to use an M6x1.0 thread but use any size fitting you have a drill bit and thread tap for, 1/4-28 is a similar size, commonly available fitting.

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What options are available for right hand drive (RHD) applications?

There are currently 3 options for RHD applications. The first is to locally source an McQuay-Norris FA5040GL idler arm and then install the bronze bushings in that and install that idler arm on your vehicle. The second option is to make a hybrid idler arm, using your existing RHD idler arm bracket (i.e. the part that bolts to the frame) and a LHD McQuay-Norris FA5040 or the ProForged idler arm (using just the internal shaft and arm portion that is identical between LHD and RHD applications) then install the bronze bushings in your RHD bracket and install the LHD shaft and arm into that. In order for that to work, you need to check that the inner diameter (ID) of the bushing holes in your bracket match the outer diameter (OD) of the bronze bushings, that being 0.952" or 24.2mm. The third option is that we have heard from a few RHD customers, that they were able to get a suitable fit of the bronze bushings with their OEM idler arm, perhaps with a little sanding or filing to get the bronze bushings to fit inside the OEM idler arm housing.

If interested, we can supply the shaft and arm section of a ProForged idler arm with the bronze bushings without the LHD cast steel housing. This combination can ship for less than the full arm + mounting bracket since it weights less. Simply order the Pro-Forged arm/RHD option below...

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On-line Ordering:

NOTE: While this has been a very popular product for us, at this time we're not able to continue offering it for sale. If any individual, group or company would be interested in acquiring the rights to the idler arm bushing design, please contact us. We can set you up with the CAD files and a high quality US manufacturer of these bushings.

If you want to have a go at making your own bushings, we have made the design files available for personal use here. There are 3D printable model files as well as a dimensioned drawing file and instructions for modifying a readily available bronze bushing with a manual lathe to fit the 20mm shaft idler arms.

We used to offer 4 options for your idler arm needs:

For shipping times and methods, see below.

The idler arm bushings are US$29.00/pr. plus shipping - SOLD OUT

Idler Arm Bushings Idler Arm Bushings Idler Arm Bushings
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Idler Arm Bushings
US First Class Mail		 Idler Arm Bushings
US Priority Mail		 Idler Arm Bushings
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Idler Arm:

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Idler Arm:

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Idler Arm:

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Pro-Forged Idler Arm Bushings
US First Class Mail		 Pro-Forged Idler Arm Bushings
US Priority Mail		 Pro-Forged Idler Arm Bushings
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Idler Arm Bushings Idler Arm Bushings Idler Arm Bushings

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.Shim stock:
US First Class Mail		 Idler Arm Bushings + shim stock:
US Priority Mail		 Idler Arm Bushings + shim stock:
Int'l Priority Mail
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Idler Arm Bushings Idler Arm Bushings Idler Arm Bushings
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20mm Sleeve:
Add-on to order		 20mm Sleeve:
US 1st Class Mail		 20mm Sleeve:
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zerk zerk zerk
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Shim washers:
add-on to bushing or idler arm order		 Shim washers:
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zerk zerk zerk

Zerk Thread:

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Grease fitting:
add-on to bushing order		 Grease fitting:
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Pro-Forged Idler Arms

Note: If you have a local retailer of this part that offers an extended/lifetime warranty, by all means purchase the arm from them and get the bushings from us. What do I do if I bend/break my idler arm?

Here's some Amazon links if you want to go that way, by all means purchase the arm from them and then install the bushings yourself. If you use one of our affiliate links below, we earn a small commision:
ProForged 102-10045
ProForged 102-10052

Pro-Forged Idler Arm With Bushings

- SOLD OUT

Note: If you have a local retailer of this part that offers say a lifetime warranty, by all means purchase the arm from them and then install the bushings yourself.

What do I do if I bend/break my idler arm?

Here's some Amazon links if you want to go that way, by all means purchase the arm from them and then install the bushings yourself. If you use one of our affiliate links below, we earn a small commision:
ProForged 102-10045
ProForged 102-10052

Available idler arm with the bushings pre-installed and ready to go. Cost: US$159.00 (p/n: IdlerArmKit). We need some time to schedule the bushing installation, so expect some delay in filling your order:

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Pro-Forged Idler Arm+Bushings/Installed
US shipping		 Pro-Forged Idler Arm+Bushings/Installed
Canada shipping		 Pro-Forged Idler Arm+Bushings/Installed
International shipping

Right Hand Drive:

- SOLD OUT

And for Right Hand Drive (RHD) applications, we are now offering the idler arm+bushings less the heavy left hand drive frame bracket so that you may retrofit the ProForged arm and bushings into your existing RHD frame bracket. You may need to open up the bushing areas of the tube in your RHD bracket slightly to fit the bronze bushings. This can be done with a Dremel and sanding drum or a die grinder and round grinding stone or sanding drum or even a hand drill. The benefit of the RHD arm option is it saves over half on the international postage as it drops the weight under the 4 lb. USPS flat rate envelope limit. Another option is that we've had customers install a LHD idler arm on the right side frame rail. You'll need to drill some new holes to line up with the mirror image bolt pattern on the idler arm housing.

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Pro-Forged Idler Arm+Bushings/RHD
US Shipping		 Pro-Forged Idler Arm+Bushings/RHD
Canada shipping		 Pro-Forged Idler Arm+Bushings/RHD
International shipping

Shipping times:

Be sure to supply an address that accepts US Post Office mail deliveries and be sure the address is valid.

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[Last updated: 13.August.2024 ]

Visitor # 75831 since 15.DEC.2010