youtube.com/pb_garage/smart_451_exhaust_leak_diy_repair

2 excerpts.

Excerpt

youtube.com/pb_garage/smart_451_exhaust_leak_diy_repair · p. 1 · Applies to: 450, 451, 452, 453, 454, #1, ebike

hey guys welcome to pb garage today we're having a look at replacing the flex pipe on a smart 451 this uh one in particular is a brabus and we're also going to look at securing this heat shield a little bit better on that catalytic converter very common issue for those heat shields to corrode away so the first thing we're going to do here i've got my little section of replacement flex pipe there and i'm just going to mark both pipes so that i know where to make my cuts once the exhaust is off the car and i'll just make it easier for when i'm jigging that exhaust back up and preparing to tack weld everything in place i know that i've got the correct lengths the next thing i'm doing i'm just going to take this scissor jack and i'm going to set it to the right height for those exhaust tips because once i cut that flex pipe out i'm actually going to reinstall the exhaust onto the car and it's not going to be held there by anything so it's not going to want to sit level it's going to want to rotate and this way i'm just setting the height so that when i weld my pipes back together i know that those exhaust tips are going to end up in the middle of the cutout in the bumper now if you have a non-brabus car which is probably most of them most of you out there uh the exit for the exhaust is up over on the right hand side and one of the telltales of a completely failed flex pipe is that that muffler will actually spin and it'll melt the bumper a little bit but in this case i've already had the exhaust off so you can see it's very easy for me to remove those bolts that are holding the flange to the catalytic converter and now i'm just going to slip it out of my rubber hangers now those bolts that hold the muffler to the catalytic converter can be a real pain in the butt and often what happens is the head of the bolt will actually snap off and then there's two nuts that are welded to the flange on the catalytic converter and what i like to do just to make my life easier in the future i snap those nuts off so that it's easier to get at everything when i'm working on it now the next thing i'm going to do is i'm just flattening out the studs so similar thing happened with the bolts that hold that heat shield in place even though the heat shield was rotted through uh when i went to remove those bolts the heads just snapped right off so what i'm trying to do here is just smooth those um bolts down or the what's left of the shank of the bolt because i wasn't able to turn them out at all and then i'm going to drill and tap through the nuts that are welded you can see the nuts are welded to the underside of those little brackets uh so i'm gonna drill i'm gonna tap and then that would allow me to put a bolt back through the original nut just like it was from the factory so we're just going to tap those nuts now and the one on the left-hand side actually worked quite well i was able to tap it fairly easily and get a bolt in there no problem but when i tried to tap the nut that's on the right hand side unfortunately my tap snapped off a little bit of colorful commentary for the tap right there but you know this happens i try to take my time but sometimes it's just not in the cards so instead of doing that root what i ended up doing was just punching the nut off of the bracket it's just held on with uh four little tack welds so i threw the bolt in the other side and punched it through as well just to be consistent so both sides i'm going to use a bolt and a nut instead of the captive or welded nut and you can see that's the nut that's welded to the underside of that bracket normally so we're going to throw our heat shield back on here and then with some quite large fender washers i'm just gonna send that um bolt through now i went up a couple of sizes on the bolts i think those are m8 thread bolts and i had to open up the hole on the bracket just a tiny little bit and even then they were quite tight you can see i'm screwing it through the actual bracket but then i've got a nut on the underside and i'm just using my screwdriver here here's a little pro tip there uh you can just wedge the screwdriver between because you can't get a wrench in there you just wedge that screwdriver between one flat of the nut and the edge of the bracket and that lets you tighten those bolts up so a bit of a trick there hopefully i never have to take this part again if so i might have to just uh cut those bolts off or something but um i'm hoping that this is it for that heat shield if it comes to that i'm replacing the heat shield anyways and then we just throw our o2 sensor back in make sure that's good and tight and now we can move on to finishing up the replacement of our flex pipe so taking out that flex pipe junk that

Excerpt

youtube.com/pb_garage/smart_451_exhaust_leak_diy_repair · p. 2 · Applies to: 450, 451, 452, 453, 454, #1, ebike

thing and then i'm just gonna put the muffler back on you can see i don't have the flex pipe in the little extension on just yet because i want to make sure that before i tack those pieces together that in fact my muffler tips are in the right spot that the muffler muffler's sitting sort of vertical and is positioned properly so now i'm just throwing my flange on with a little piece of pipe that i've cleaned up with the grinder and i'm just going to hold that in place with the couple of bolts on the flange there there's my new piece of pipe so i'm just going to get my height gauge get my jack in the right spot there and then i'm throwing a bungee cord on it just to rotate that muffler a little bit so that it sits in the right position nice and sturdy and then throw my pipe in [Music] and this way i know when i tack that together everything's gonna line up right and it's time to make some sparks now i'm not gonna try and weld this all together uh while it's on the car all i'm gonna do is put a couple spots on it to make sure that everything stays where it should be once i take it off because then i can work on it off the car and more importantly then i'm not welding above my oil soaked carpet which probably isn't the best idea now fast forward a little bit here i've welded that all up you can see my pipes welded all the way around there i'm just reinstalling everything with a brand new gasket that's very important to put a brand new gasket in there because those things fail quite easily especially when they're old when you take that apart it'll just fall to pieces in your hands so i can go ahead and tighten my um bolts up properly there and then i'm just going to start the car and i'm going to make sure that i don't have any leaks anywhere in that pipe to make sure that my welds are good and that the gasket is sandwiched in there properly and nothing's leaking so like i say this is a brabus exhaust um so it should sound a little bit more sporty i'm sure you can tell from that clip but that's it uh thanks for watching guys hopefully you have a successful repair on your own muffler at home and um we'll see you next time [Music] you