Smart42

I know this is an old thread, but my EGR valve started leaking oil past the cartridge. There is a square O-ring near the top of the cartridge that needs replacement, does anyone have a part number or sizing for it? For now I put some Teflon tape around the top and reinstalled it which has stopped the leak for now.

I was glad the spring broke while I was working on the car, not driving it. Back on topic: I had a look at the front bearing; it would be difficult/impossible to put a grease nipple in there that would be accessible without removing the wheel, caliper and rotor. Once you have done that you might as well pull the bearing out. Also; the nipple would be installed in the turning portion, unlike the rear. The only workable option I see would be to drill a hole in the post the bearing mounts on and use/fabricate a bearing greaser tool similar to the one below that fits in the 12mm hole for the hub bolt. Grease would flow via the greaser through the hole in the post, between and around the inner races to the bearings. To service the bearing you would remove the hub cap and hub bolt, insert greaser, grease and reverse. If you have the bearing out and you do not want to take it apart a 28mm bearing greaser (if you can find one..) should fit.

So decided to put on my summer tires, clean the brakes and grease my bearings. Took the front wheels off, removed caliper, dust cap and hub bolt. Wheel bearing came off easily. Turned around to grab a tool and hear a loud clunk. My front spring decided it had enough, broke the bottom coil so the rest came down over the strut. I guess lubing the rear bearings will have to wait until the new springs are installed....

The thing that holds the bearing together when mounted is the pressure exerted by the nut of the drive shaft in the back and the hub bolt in the front. Thanks for your explanation!

I do not understand: if you drill a hole in the spot I suggested you would hit one of the bearing cases in the hub? That was definitely not the case with the Subaru bearing I experimented with.

My Subaru bearing is the same design. I cannot see a separate pressed in outer race. I would think the outer race does get some kind of surface treatment after machining?

Looking at Tolsen's dissected bearing, no. No reason to have seals inside; the housing is filled with grease. It is contained by the 2 external seal and the 2 inner races pressed together.

So found this picture and tried to draw in my proposed grease nipple (white) and the flow of the grease (red) to the bearings.

There does not need to be a hole in the race. The 2 inner races do not contact the hub anywhere. They rest on the ball bearings on either side and are firmly pressed together in the middle when the bearing is mounted. The grease is injected in the bearing body and flows over the outside of the inner races to the ball bearings. No need to grind the races; the ball bearings ensure there is space in between the balls for the grease to flow through. Why are you guys so set on damaging the races???

if the bearing is disassembled like you did, simply clean it out; which of course is best practice as long as other components are not damaged during the process. Or, drill carefully and blow swarf away frequently. Last bit slow with a greased drill to catch swarf without taking it apart. What do you think will happen if a wee amount of soft metal swarf gets in to a large bearing with hard steel components? These are not high speed precision bearings designed to spin at 100K RPM. At 120 km/h they spin at 1100 RPM. Tough crowd here this week: first y'all say it is impossible to drill a hole where I proposed. Only with a mill with top quality bits or spark eroder. Then I show you proof it can be done readily. You do not believe I used a bearing, and I show you I did. Now we fuss about a possible fleck of soft metal entering a hard metal bearing designed to operate in a dirty environment..

Here are a few more pictures. First one shows the bearing with the inner race in place and a bolt through my drill hole showing where the grease would flow. Second shows the same with the inner races removed. Third is a close up showing the front inner race removed, the rear inner race in place and the bolt through the hole on the bottom. The grease would flow between the inside of the bearing body and the outside of the inner races to the ball bearings and out the seals. There is space between the inside of the bearing housing and the inner races where my drill hole is. I am sure the races are hard metal, but the body in between clearly is not and this method avoids touching the races. It is enough to drill a hole and use a drive in grease fitting no tapping necessary. With careful drilling, blowing the chips out frequently and using a greased drill bit for the last bit the amount of cuttings getting in to the bearing will be minimal. This might be doable with out disassembling the bearing or even removing it from the vehicle.

I did not have an old Smart bearing laying around, but had an old Subaru Outback bearing (made by NTN, USA) on my bench. I decided to give it a try and see if Tolsen and Willys were right. I started with a 1/4" cobalt drill bit and, to my surprise, was able to drill through the bearing body freehand. Then I used a HSS 13/64" bit to enlarge the hole and finally a cheap Canadian Tire 1/4" 20NC tap. I was able to drill and tap the bearing with simple hand tools and little effort. If someone has an old Smart bearing around I would be very interested to hear if they drill as easily as my Subaru bearing.

Looking at the images you posted in your excellent thread about the rear bearings: why not drill a hole and fit a grease fitting in the center of the hub? It would inject the grease between the 2 ball bearings and negates the need to grind a path in the race or drill the bolt. For access it would require removing the brake drum, but you only need to grease them once a year or less.

Posted in another thread as well: Question: looking at Tolsen's photos of the bearing I understand there is an outer and inner bearing each with their own race. I assume the rear is the same? This is similar to those found on ATVs, like my Arctic Cat. To grease those bearings you can now get a bearing greaser, see picture below. The tool injects the grease between the two races. The pressure is enough to push the races slightly apart allowing the grease to flow in to the bearings. This works slick in my ATV, so I wonder if it would work for the Smart too? Would make greasing the bearings an easy maintenance job. Does anyone have measurements for the inner diameter of the bearings and the depth to the middle between the races?

Question: looking at Tolsen's photos of the bearing I understand there is an outer and inner bearing each with their own race. I assume the rear is the same? This is similar to those found on ATVs, like my Arctic Cat. To grease those bearings you can now get a bearing greaser, see picture below. The tool injects the grease between the two races. The pressure is enough to push the races slightly apart allowing the grease to flow in to the bearings. This works slick in my ATV, so I wonder if it would work for the Smart too? Would make greasing the bearings an easy maintenance job. Does anyone have measurements for the inner diameter of the bearings and the depth to the middle between the races?