Jimny 5 Door Revised Kingpins | From DIY to WID

Kingpins

Maruti Suzuki had put out a service bulletin (M-Q-CM-113) regarding the wobbles when you brake to slow down from around 80KpH to 60KpH which they have identified the cause as 1) brake rotor runout and warping and 2) kingpins not putting enough preload on to the swivel knuckle.

In my Jimny I continued to use stock brake rotors which came from the factory till 20000Kms with a pad change in between which had taken care of the wobble until the brake rotors were seriously gone and the right side brake system developed a sticky caliper. But still they were OK until repeated braking which got them hot and the wobbles ensued.

So it was deemed necessary that I renew the brakes and whilst doing that change the kingpins also on my expense as they don't cost much and also I don't have to follow their SOP of wheel alignment and balancing at the dealer service network to make the warranty claim.

The friendly MGP dealer in our region was able to source 4 kingpins with the revised part number 45610M80T01 and the outgoing kingpins are 45610M80T00. Jimny's made from Oct 2024 would have come equipped with the revised kingpins.

New kingpins

In the box

Measurements

Finally the critical measurement which would actually determine the preload on the bearing. Height from the base to the ledge that meets with bearing inner race, which is 14mm.

Let us compare the critical measurement with the old kingpin 45610M80T00

The height from the base to the first deck of the T00 kingpin is measured at 13.7mm. The new T01 kingpins are 14mm. This in effect is putting a 0.30mm shim on each kingpin.

The 3 door Jimny kingpins have a deck height of 14.36mm which is about 0.36mm more than the Jimny 5 door kingpin deck height.

In the comparison of T01 5 door kingpin with 3 door kingpin the former's deck height is still not where the JB74 is at. But 3 door and 5 door Jimny does not use the same kingpin or kingpin bearings; the 5 door's kingpin has a thicker spindle and because of this they use a different tapered bearing and probably a different outer race on the swivel ball. So In my opinion an estimation and comparison of preload (3 door/5 door) based just on deck height of kingpins alone would not be accurate.

 

The JB74 kingpin measurements and photos were sent by Liam Setford, from the Australian Jimny group. All credits to him. 

DIY Part

I did the installation myself, did not have a lift so front axle was jacked up and left on jack stands. Both wheels were removed, the brake caliper was removed but left the rotors as is as. Loosened the four M8 bolts holding each kingpin and took out the old kingpin, but one at a time. There was old residue of the factory Grey sealant (probably Suzuki branded Threebond) which I scraped off with a wire brush. before doing that put some cotton into the spindle hole to catch any debris that might fall into the swivel hub. The wire brush made quick work of the old sealant and the surface was perfectly clean.

Sealant was applied on the base of the new kingpin and smeared it around the sealing surface and put the new kingpin into the hole in the steering knuckle. It went in with some wriggling, shifting and few knocks with a rubber mallet. The bottom kingpins were more trouble to get in properly and needed some pulling of the knuckles outwards to get it in. I didn't have the Suzuki Grey sealant which is probably some grade of Threebond in Suzuki packing instead I used Loctite Blue Max 587 which should be good.

Whilst the installation was pretty straightforward but it was not without an unpleasant surprise and very similar to the Internet meme "It was at this moment he realised...." situation. I managed to break one bolt on the top LHS kingpin whilst tightening it down. I was not using a power tool, nor was I using an extension handle but just a standard length Taparia 1/2" ratchet handle. The bolt did not give any indication that it was about to give up but it suddenly did. Of the total 16 bolts 1 failed, I did the other 15 with no problems.

So since I used Loctite blue threadlocker on all bolts, I quickly undid the LHS top kingpin and sprayed some rust penetrant fluid on the broken bolt. Did this repeatedly till the fluid disappeared. Did this to other three bolt holes also. In the hope to possibly prevent the Loctite 242 from curing which would make extraction difficult later. Once the kingpin was again assembled with the remaining three bolts I applied the penetrant fluid into the cavity of the broken bolt. Did this a few times.

Re-Using/Not Re-Using Kingpin Bolts? Maruti Suzuki service centers re-use the original kingpin bolts with the new kingpin. Kingpin bolts are not marked as "do not re-use" items in the service bulletin. In the Russian translated workshop manual for the JB74, kingpin bolts are not marked as "do not re-use" items (there are other bolts which are, for eg: radius arm mounting bolts are marked "do not re-use"). The recommended tightening torque for kingpin bolts are 25NM which is fairly under 28.8NM max tightening torque of SAE grade 5 (Metric grade 8.8) bolt used in the Jimny. Probably why they don't consider it as a "do not re-use" item.

New kingpin bolts would be best practice. But if re-using (not these grade 7 bolts!), a dab of medium strength (blue) Loctite thread locker would be appropriate because the factory bolts come pre-applied.

On closer inspection I found the M8 bolt was marked RTF 7. Which translates as Metric Grade 7 bolt manufactured by Right Tight Fasteners. I find this strange because the international 3 door Jimny has SAE Grade 5 bolts for the kingpins.

Below a sample photo of the OEM kingpin bolt for the Jimny 3 door which I found on Jimnybits website. This is an SAE graded bolt. SAE grade 5.

There are aftermarket kingpin/swivel hub overhaul kits sold by vendors which carry Metric grade 8.8 bolts. I have not seen a kit using a bolt below Metric grade 8.8 for the Jimny's kingpins. Photo below from Lamberts in UK.

SAE Grade 5 converts to Metric Grade 8.8

So technically an inferior grade 7 bolt is used in the Jimny 5 door. Why? Mine was manufactured in the second quarter of 2023 and one of the earliest models. No one has fiddled with its kingpins until now. I am not saying the bolt broke due to being inferior grade, I don't know that probably not because I did not use full force  or put my weight on the ratchet on that M8 bolt.  But what I know is quality fasteners in my part of the world are made by TVS,  Unbrako, Caparo, LPS etc amongst others. I haven't heard of RTF before this bolt broke.

Edit 14/06/2025: If these bolts are JIS standard grade 7 bolts they are equivalent to Metric grade 8.8 bolts. But as I stated above I don't think the bolt broke because (at that time I thought it was inferior grade) of its grade. 

The WID Part

This is the "Watch it Done" part, and this section deals with the extraction of the broken bolt which I managed to accomplish. My job is to just "watch it being done".

So off I went to the friendly neibourhood garage to meet my friendly neibourhood mechanic to present him with my problem. I made it abundantly clear to him the iffy quality of the OEM RTF (what an apt name) branded M8 grade 7 bolts but I doubt it went through. But anyways it did not matter. Plan was to spot weld another bolt on top of it as couple of threads were visible above the deck line.

Preparation for spot welding was in progress with tubes and wires shielded with an old number plate belonging to some other vehicle and that's when our mech  friend thought he would try to grab that bit by the end of pliers and give it a twist to see if it budges. Honestly I had no hope of it moving and asked him to not waste time with it and proceed with spotting another bolt over it.

But surprisingly the broken bolt did move a bit counterclockwise with the pliers. Damn! It moved! He readjusted the pliers and it moved a bit more. So out came a long screw driver aka chisel driver and a small hammer and he tapped away at it with the bolt turning counter clockwise with each tap.

Once a few threads got exposed he went for the pliers again and there it was in my hands within a few minutes.

That ^^ was a major relief for me. Over the last couple of days I have been playing and replaying the worst case scenarios over and over in my head.

All stock 16 M8 Metric grade 7 bolts would be replaced with better quality and higher grade bolts as soon as I get them delivered. He has temprarily installed the kingpins back using available bolts.

How does it drive?

Its been just a day since LHS top kingpin was again secured by four bolts. So haven't ventured out for longer highway drives yet. But right away noticed that steering has become a wee bit tighter compared to  how it was before. I could feel this in turns and also how the steering re-centers itself after completing a turn. So if this is the new kingpin putting an additional pre-load on the bearings it is expected behaviour and seems to be working.

Bolternatives? And back to DIY!

So what are my alternatives aka bolternatives for the OE Run To Failure RTF metric grade 7 bolts? There are a few actually starting with ubiquitous good quality Sundaram Fasteners (TVS) bolts which I bought from a local shop today. TVS makes good bolts. But because they make good bolts and are popular it is easy to land a fake. But these i think are genuine. TVS M8 10.9 25mm and TVS M8 8.8 20mm.

From left to right: TVS 25mm 10.9, Caparo 25mm 12.9 Allen, TVS 20mm 8.8, OE 20mm RTF JIS7(?) and on the extreme right wedge lock washers. Suzuki use standard pitch bolts for the kingpins and so easy to find alternatives.

The bearing area under the TVS hex head and Caparo socket head bolts seems to be the same. The former has a well defined bearing area under the bolt head. TVS 20mm left and Caparo 25mm socket head right.

With OE 20mm bolts with the captured compressed spring washer the threaded part of the bolt that engages with the threaded bore on the knuckle is 9.62mm. With a standard 20mm bolt with the wedge lock washer only 8.06mm of the threads will engage with the knuckle. If I use a standard 25mm bolt with the wedge lock washer there is about 13mm of thread engagement with the knuckle.

The problem with 25mm bolts when when torqued is that they are almost at the limit of bottoming out, but not exactly bottomed out. On the top kingpins where the two bolts per side hold the vacuum lines clamp 25mm bolts seems safe to use. But for all other locations they are at risk of bottoming out when torqued. Wedge washers supposedly don't work that well if stacked so stacking two washers to take out the height will not help.

But I am forced to use the 25mm TVS 10.9 bolts with a wedge lock and a high tensile spring washer stacked below. This seems to work bolt length wise. So for now this should do till I procure 22mm bolts to use with wedge lock washer alone, these seem to run late and I need to get this kingpin saga to be done with already!

And this time decided to dig out the torque adaptor and torque it to 27NM (workshop manual recommendation is 25NM). All 16 bolts were changed to TVS 10.9 and torqued to 27NM.

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