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Cam belts
Feb 5, 2023 11:05:33 GMT
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Post by andy on Feb 5, 2023 11:05:33 GMT
Until recently I used to buy cheap runarounds for £500 with 12 months MOT and then drive them until they died*. I'd usually get 2-3 years out of them until they required a big bill paying out, at which point I'd scrap them and start again. To the best of my knowledge none of them had had timing belt changes and all of them had done over 120,000 miles and none of them suffered a timing belt failure. * There were some gems to be had if you weren't picky about make or model. There were lots of good cars that dealers offered peanuts as trade-in value. Sadly the government subsidy in the form of the scrappage scheme pushed the prices too high. With the new low emissions zones coming into force there might be a bunch of cheap cars for sale soon. The likes of the old 3 litre BMW diesel isn't ulez compliant apparently and they are supposed to be quite good....if you like that sort of thing. Should be lots more cars that aren't worth paying £12.50 a day to drive in a ulez zone. |
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Post by mick on Feb 5, 2023 11:28:06 GMT
While we are discussing car maintenance, what do our experts think of the modern trend to replace brake fluid.
I'll say more when I get back from my first camera trip of the year!!
Mick
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Post by Deleted on Feb 5, 2023 12:04:42 GMT
I have decided to keep the car and have the cam belt changed. I have been quoted a price by the main dealer, which is consistent with my expectation and have asked for a price from a local independent garage. When I had the cam belt replaced on the Octavia I went to the local garage I have used on and off for years but it probably would have been cheaper at the main dealer. I won’t ask them to quote for the Fabia. Cool, don't let them just do the cam belt the kit should have tensioners / idlers and ask if the water pump is driven off the cam belt, if so have that changed at the same time as compared to labour costs involved the water pump is almost a consumable. VAG water pumps used to have plastic vanes which deteriorated and broke up over time, I don't know if they have improved them since my Audi owning days, I don't expect they have. Thanks, all the advice and the quotes is to have the water pump done at the same time. It was the water pump on the Octavia that required replacing and the did the cam belt and the same time. I think the garage said it all came on the same kit. Having partly retired I was considering reducing our cars from 3 to 2 as a car each seems excessive. However, given the insurance costs my daughter would have a share the smaller car with my wife with the wife and I sharing the larger more powerful car. It would probably work but there would be several occasions where we needed 3. (Perhaps needed is the wrong word). Car prices, both new and used are still in an unusual place. The prices for our cars from the likes of WBAC are higher than expected but the costs of replacement cars are likewise higher. They are also in short supply. So I will get the servicing up the date, replace the cam belt and that should keep us going for a while. |
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Post by geoffr on Feb 5, 2023 12:23:22 GMT
While we are discussing car maintenance, what do our experts think of the modern trend to replace brake fluid. I'll say more when I get back from my first camera trip of the year!! Mick Brake fluid is hygroscopic so, after a period, it will have a lower boiling point due to the absorbed water. A low boiling point isn't a problem for the first brake application but if the fluid is heated above the nominal boiling point it may boil when you release the brakes. When you then reapply the brakes you have to compress the gas and effectively have no brakes. Change the fluid regularly and it won't come to that. |
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Post by petrochemist on Feb 5, 2023 13:04:44 GMT
While we are discussing car maintenance, what do our experts think of the modern trend to replace brake fluid. I'll say more when I get back from my first camera trip of the year!! Mick Brake fluid is hygroscopic so, after a period, it will have a lower boiling point due to the absorbed water. A low boiling point isn't a problem for the first brake application but if the fluid is heated above the nominal boiling point it may boil when you release the brakes. When you then reapply the brakes you have to compress the gas and effectively have no brakes. Change the fluid regularly and it won't come to that. Geoff has that spot on, but bleeding the system can also remove water vapour. If you don't drive hard the slight sponginess produced by old fluid is not too serious, but racing teams typically replace brake fluid every event as well as using higher grade fluid. Topping up & occasional bleeding (every 2-3 years) was perfectly sufficient for the classic Celica I drove for 100,000 miles. |
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Post by geoffr on Feb 5, 2023 13:12:46 GMT
Brake fluid is hygroscopic so, after a period, it will have a lower boiling point due to the absorbed water. A low boiling point isn't a problem for the first brake application but if the fluid is heated above the nominal boiling point it may boil when you release the brakes. When you then reapply the brakes you have to compress the gas and effectively have no brakes. Change the fluid regularly and it won't come to that. Geoff has that spot on, but bleeding the system can also remove water vapour. If you don't drive hard the slight sponginess produced by old fluid is not too serious, but racing teams typically replace brake fluid every event as well as using higher grade fluid. Topping up & occasional bleeding (every 2-3 years) was perfectly sufficient for the classic Celica I drove for 100,000 miles. I have heard of instances of brake lines failing due to internal corrosion, personally I'd rather change the fluid every couple of years than the hydraulic pipes. Mine was replaced last year when I had a calliper replaced, if you are going to make a hole in the system it makes sense to replace the fluid at the same time. |
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Post by mick on Feb 5, 2023 16:55:42 GMT
Here's my take (back from my trip!!).
Yes brake fluid is hygroscopic but it's contained in a sealed system. If the system sealing fails then the brake fluid escapes and the driver knows about it pretty quickly! Water doesn't enter the system - at least not in quantities large enough to cause a problem.
If water did enter then one would have to get the brakes pretty hot for there to be a problem. Much, much hotter than the average driver would ever manage.
I therefore think that brake fluid change is unnecessary and is a catchpenny dreamed up by the motor industry.
Despite what's written above a friend agrees with me. He was the chief hydraulics engineer for one of the best known F1 teams.
Mick
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Post by Bipolar on Feb 5, 2023 18:00:46 GMT
Years ago I bought an older Ford car that had almost double the recommended kilometres on it for the timing belt to be changed. I replaced the belt and noticed afterwards an improvement in performance and fuel economy.
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Post by peterob on Feb 5, 2023 18:20:58 GMT
I’ve had the brakes fade with boiling hydraulics. Full volvo 240 estate towing big and loaded trailer tent, whole family in it. Coming back across Wales, long, winding descent. Fortunately a long straight at the bottom. Pumping like mad stopped with handbrake. No fluid loss, it just all got too hot. Sample and test brake fluid ( there is a standard method) ever two years and replace if in any doubt is my advice.
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Post by nimbus on Feb 5, 2023 18:22:36 GMT
No advice but when we were quoted £800 to replace the cam belt on our VW touran we ignored it. Cam belt went and killed the car on the way to collecting our daughter from hospital. That seems excessive. |
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Post by gray1720 on Feb 5, 2023 19:26:35 GMT
I’ve had the brakes fade with boiling hydraulics. Full volvo 240 estate towing big and loaded trailer tent, whole family in it. Coming back across Wales, long, winding descent. Fortunately a long straight at the bottom. Pumping like mad stopped with handbrake. No fluid loss, it just all got too hot. Sample and test brake fluid ( there is a standard method) ever two years and replace if in any doubt is my advice. Could have been much, much worse - I recall someone with a classic car at a track day being killed or badly injured back in the late '80s when the brake pedal went to the floor, believed to have been caused by the brake fluid boiling. The other issue is that old, damp, brake fluid munches the seals on the cylinders - again, potentially leaving you brakeless. I'm with Pete on this one! |
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Post by davem399 on Feb 5, 2023 19:38:54 GMT
My brake fluid is renewed every two years as per the servicing schedule. The brakes definitely feel sharper when I pick it up from the garage after the service.
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Post by davem399 on Feb 5, 2023 19:44:20 GMT
Here's my take (back from my trip!!). Yes brake fluid is hygroscopic but it's contained in a sealed system. If the system sealing fails then the brake fluid escapes and the driver knows about it pretty quickly! Water doesn't enter the system - at least not in quantities large enough to cause a problem. If water did enter then one would have to get the brakes pretty hot for there to be a problem. Much, much hotter than the average driver would ever manage. I therefore think that brake fluid change is unnecessary and is a catchpenny dreamed up by the motor industry. Despite what's written above a friend agrees with me. He was the chief hydraulics engineer for one of the best known F1 teams. Mick The brake system is not sealed, the reservoir cap has a small hole in it. |
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Post by geoffr on Feb 5, 2023 21:23:10 GMT
I’ve had the brakes fade with boiling hydraulics. Full volvo 240 estate towing big and loaded trailer tent, whole family in it. Coming back across Wales, long, winding descent. Fortunately a long straight at the bottom. Pumping like mad stopped with handbrake. No fluid loss, it just all got too hot. Sample and test brake fluid ( there is a standard method) ever two years and replace if in any doubt is my advice. Yes, one uses a hydrometer simply draw up a sample of fluid and read where the surface of the fluid sits relative to the scale, just make sure to use the right one. |
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Post by mick on Feb 6, 2023 0:45:49 GMT
Here's my take (back from my trip!!). Yes brake fluid is hygroscopic but it's contained in a sealed system. If the system sealing fails then the brake fluid escapes and the driver knows about it pretty quickly! Water doesn't enter the system - at least not in quantities large enough to cause a problem. If water did enter then one would have to get the brakes pretty hot for there to be a problem. Much, much hotter than the average driver would ever manage. I therefore think that brake fluid change is unnecessary and is a catchpenny dreamed up by the motor industry. Despite what's written above a friend agrees with me. He was the chief hydraulics engineer for one of the best known F1 teams. Mick The brake system is not sealed, the reservoir cap has a small hole in it. The system needs to be vented. Not all caps have ‘holes’ but those that you think have holes have ( from memory) something called a convoluted membrane behind them specifically to stop water ingress. I should have said sealed from moisture rather than just sealed. Again from memory a typical car hydraulic fluid will have a dry and wet boiling point at 270 and 170 deg C. Recently I had cause to measure my front disk temperatures after various journeys. The highest temp I recorded was 70 - and that was with a faulty calliper that was not retracting fully. I’m no expert though so I won’t push it any more. I’ll just add that, like the car, the fluid has also done 200k so far without mishap. Mick |
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