District Calendar - d37
First you need a hammer, punch, gloves, safety glasses, a torch and a piece of scrap wood to go between the hub and whatever surface you're hammering the hub on. After removing wheel from the hub you should be able to get the seals and bearings out with basic tools (Keep the seals for the time being). Once you have those out you need to get the inner bearing races off, which is the more challenging part. To do that you heat the hub it using a torch until the bearing grease starts to drip out, then hammer the races out using the punch. There will be grooves machined out of the hub to do this, you just hammer one side, then the other until it drops. Flip and repeat for the other race (assuming you have 2). Keep the old races.
How to remove astuckbearingfromashaft
There's a good section on the TDI Club's FAQ about timing belts, as that's what Volkswagon uses on all their turbo diesels. A belt breaking on a TDI is catastrophic. As far as I know, most cars use chains and compression ratios low enough that there's no risk of piston heads smashing into an open valve should the chain break. You can't retrofit a belt system to use a chain, you wouldn't want to do the reverse, but I have seen people replace belts and chains with direct gear drives.
I own a 2013 Volkswagen Golf TDI. Just recently, I drove a one year NEWER 2014, VW, with a 2.5, 5 cylinder Sportwagon. The 2.0 TDI, and the 2.5 Gas Engine, get the SAME Fuel mileage in town. Its the TDI that saves fuel on the freeway. Yes, the 2.5 Gas engine has the timing chain, and will last the lifetime of the car. The TDI is economical on the freeway, but its HIGHER cost in the beginning, @ purchase, and it's timing belt maintenance/replacement, is why I am going to trade my diesel in, for the gas engine with its timing chain, very soon.
BearingPuller
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Next clean the hub up, remember it's still hot! Get all the grease, grime and dirt off or it's going to get into the new bearings. Inspect it for cracks while it's clean.
How to remove bearingfrom shaft with puller
all these answers are right and correct the simple answer is often it can be done with a simple threaded rod and washer spacer and nut setup given mentioned, it was designed to be replaced if fuck all else won't work or you simply don't have any other means sadly some times the only answer is to replace the part. which is the manufacturer being a greedy so&so. if you have the option do it yourself is always best. they make ratcheting box end wrentchs these days, get yourself a proper set. getting proficient in doing things yourself is ever gratifying it makes you strong inside where it counts. The spacer can be made from stock and rifle drilled or heavy walled tubing again sometimes the best tool for the job is the one you make. and then you will have it forever/Threading dies for ID AND OD are always a good idea to keep on hand take good care of your affairs and you will be well kept friend. a good machinist and a mechanic is a happy man.
They have been known to break but as Brian mentioned, that's very rare. I've also heard of a more common failure mode with chains where over time the metal stretches which alters the timing, so although everything runs, your car becomes de-tuned and to fix it, requires a chain replacement.
What is the service life of a timing chain and how does having a chain drive cam benefit from a belt drive cam and vice-versa?
How to remove bearingfrom hub
How to remove a bearingwithoutapuller
Bearing race insertion: Before you try to get the new races in, you need to take the old races and cut each across using a rotary tool, saw, angle grinder or the like. Stick the new races in the freezer, this will cause them to shrink (30 minutes at least in the freezer). Heat the hub again, this will cause it to expand. Get one of the frozen races from the freezer and quickly drop it into the hole. If you're lucky the combination of the expansion of the hub and contraction of the ring may let the ring just drop straight down.
How to remove a bearingfromablind hole
Once you have the races in and the bearings greased and inserted you need to get the seals on, most of the time these are synthetic and can be tapped in with a rubber mallet, but sometimes using the old seals to protect the new ones is a good idea as well.
I think we covered this before, but I can't find it... Timing chains have much greater service lives at the expense of slightly more noise and friction, as well as a lot more damage if they break (but odds of breakage are much less than a belt).
I may not be 100% accurate but I think belts have expected lift time of 60k-100k and at 100k they should definitely be changed.
If you're me that won't happen as it's never that easy, this is where the old bearing races come in. You could use the hammer and punch on the new races directly, and I've heard of people doing this successfully without damaging them, however it's risky. Put the old race on top of the new one and hammer on that instead, the old race will spread the force out and prevent damage. The slit cut through it will keep it from getting stuck along with the new race. Work around, hammering as you go until it's seated. Note that this method can be annoying and time consuming as the old race has a habit of jumping out. Repeat for the other side, you will probably want to reheat the hub.
Belts are quieter but are often less obviously worn before they break (chains stretch and loosen, belts tend to stay tight without damaged belt teeth up until the moment they snap). Timing belts are also less complicated (chains require an oil bath). Chains are generally stronger, so vehicles with timing chains often drive more than just the cam with the timing chain. Due to stretch, when you change a chain you MUST replace all the timing gears, as the teeth will wear to match the chain stretch. While not necessary on a belt driven system, a failed gear will cause a belt failure and, depending on your engine, could be very bad, so it's generally recommended to replace all idlers and gears in a belt system, too.
How to remove bearingfrom housing
I've replaced bearings without either a puller or a press, it's perfectly doable, although a bearing insertion set does make things much easier. These are cheap and you can get them off the internet. Failing that you can do without.
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The amount of damage caused by a belt breaking vs a chain breaking entirely depends on the type of engine. Engines with really high compression ratios (performance cars that require high-octane fuel, diesels, etc) tend to have the valves and piston heads move such that they could come into contact if the cam stops opening and closing the valves. When a piston head smashes into a valve, you ruin the head, valve, and potentially other cylinders if pieces of shattered valve travel through the air intake system to the other cylinders.
In the end: The chain is a stronger, longer lasting product, that is harder to diagnose and harder to replace. When and if it breaks, it will break catastrophically without as much warning. The belt is more regularly replaced and is more telling when it is near its end of life. It is usually easier/faster to replace. Balance between Durability / Maintenance / Costs
There's other options than reusing the old races for getting the new ones in that work better, providing you can find materials of the right diameter. A length of steel pipe just smaller than the race works great, as does a big socket.
I would recommend taking the hub to a local garage and for a very small fee of around £10 they will press out the old bearing and fit the new one. I have done this several times and found the garages very accommodating. All you then need to do is fit the hub assy. Failing that you could knock them out but I recommend you take the easy option as you may damage the bearing trying to fefit it. They are very tight.