wishbone_front_lower_suspension_arm_replacement_smart_fortwo_451_suspension_knoc¶

2 excerpts.

Excerpt¶

youtube.com/auto_knight/wishbone_front_lower_suspension_arm_replacement_smart_fortwo_451_suspension_knoc · p. 1 · Applies to: 450, 451, 452, 453, 454, #1, ebike

In today's video, I'll be replacing this lower front suspension arm, often known as a wishbone, on the Smart for 251. I'm Steven from Autoite. Welcome to another video. Now, with the exception of crash damage, there are two main issues with these lower arms that can cause you problems. These bushes can wear or separate, and the ball joint can develop play. Now, both of these can cause knocking noises from the front suspension, and it can also play up with your wheel alignment and cause tire wear issues. Throughout the video, I'll be tightening fixings to various torque settings. Always do your own research and be happy with the torque settings you use when working on your car. Some of these figures can be really hard to find and verify, so don't rely on mine. Here is the replacement component, TRW part, and there's the part number. It's important to measure the distance between the center of the wheel hub and the edge of the wheel arch, which in this instance is 33 cm. The prayer mat is in place because obviously I'm deeply religious. This lower ball joint nut needs to be removed. It's an 18 mm. Using a ball joint splitter. There we go. It's released. This anti-roll bar bracket nut is released. It's an 18 mm We can move that up and out of the way. And then we can access this, which requires a 24 mm socket. These are potentially very tight. It's a little harder to see in here, but it's just about accessible. There's another 18 mil bolt for the rear inner mount. This one actually came loose quite easily. It's a little bit tricky to get in there. And this brake pipe does go up quite close to it once it's fully wound out. But you have got these little vents underneath these openings which make it easier to reach in. There's nothing really holding this to the car at this point. This now gives you an idea as to how it goes together. This is in the middle threaded at each end and it passes through like that. And there's a little bit of play in this ball joint which is the reason for replacement. Here we are. Old versus new. The new one comes with this lock nut for the lower ball joint. It's ready to go. I'll leave this on to protect it. until I do that up. I'm just going to put this piece in first. To help with alignment, I've refitted this. And I did spray some WD in here to help it slide cuz it's quite a tight fit. And I've actually just fitted these bolts at each end so it's in the correct place. Saves a lot of messing around. Now I can just loosen these and fit the arm and this should stay put. I felt this bolt slip inside. It's now in contact with the threaded piece in the middle. The ball joints in place. I'm going to pop the nut on that to stop it from coming out. This bottom bolt also located into the threaded piece. So, I can now tighten these both sides, but not fully. With both of these tightened, but not fully, just kind of handtight, plus a bit more. It's now time to tighten the ball joint nut. The center started to spin, so I needed to secure it with a 6 mill Allen key. It's starting to 46 Newton m. Do you remember earlier when I measured

Excerpt¶

youtube.com/auto_knight/wishbone_front_lower_suspension_arm_replacement_smart_fortwo_451_suspension_knoc · p. 2 · Applies to: 450, 451, 452, 453, 454, #1, ebike

the distance between here and here? and it was 33 cm when the vehicle was on the ground. Well, there's a reason for that. The inner bushes on this style of lower arm or wishbone. Well, they have a designed range of motion. So, when they're tightened, this middle part of the bush becomes fixed on the vehicle. And then any upwards or downwards movement, well, that's taken care of by the bush itself. So, if the vehicle's jacked up and it's hanging like this and you tighten it fully in this position, well, it'll do that bit all right, but that bit's going to be putting tremendous strain on the bush. Therefore, it's really important that you tighten these at the correct standard ride height. That is the starting point for the bushes and then they can go either way as they need to. I hope that makes sense. So many people don't bother with this and I've even worked in main dealers where people will just tighten stuff when it's hanging like that and you're just going to screw up the bushes early. They won't last long at all if you do that. So at this time we're at 41 cm. So I need to recreate the being on the ground situation. I usually have a big rubber block on here but that's in use somewhere else. This isn't quite the same but it'll still stop it from damaging the lower arm. Okay. And now at this point, we can fully tighten these and then torque them up. Set to 120 Newton meters. It's very difficult to get a torque wrench in on this rear one. I ended up using this and estimating the correct tightness. I generally have a good feel for torque settings. Anyway, I reposition this anti-roll bar bracket here. And we refit this 18 mil nut. 85 Newton m. Well, that's it for this one. I hope it was useful. I will likely replace the other lower arm at my leisure and off camera. Meanwhile, thank you very much for watching. I look forward to seeing you again in another one very soon. Please don't forget to like and subscribe.