StevedTR4A Posted December 15, 2008 Report Share Posted December 15, 2008 Hi all On changing the cooling hoses on my 3A I notice that the water pump housing by-pass hose connection is quite short and is slightly conical. Drawings in the maintenance manual also show the same dumpy slightly conical shape but a photo in Roger Willams restoration book shows a longer and apparemtly cylindrical connection. My concern is ensuring that I get a tight secure fit when I fit the new hose and clip. -I read somewhere that the contact surface should be "roughed up" with a file. What is the wisdom here and why is this connection conical? - (I notice that the alluminium repro is cylindrical with a bead on the outlet edge which I guess ensures a much better fit.) Any comments very welcome cheers Steve Quote Link to post Share on other sites
Don Elliott Posted December 15, 2008 Report Share Posted December 15, 2008 Mine has a taper on the OD of the aluminium casting for the thermostat housing and it slid off once when I was about a mile from home. So I pushed the hose back on, filled it with water and tried to tighen the clamp. Then I drove back home to work on it. Tightening it encourages it to slide off more. The slippery action of the antifreeze adds to the problem. A cylindrical shape here is better with a lip all around. I cleaned it up and filed the taper even more severely near the end to make my own circular lip all around. Then I put some sealant like you might use to hold the gasket and the two halves together for the thromostat housing, tightened it and let it dry for a day before filling it with a new mix of 50/50 water/antifreeze. It has been fine now for about 5 years. Quote Link to post Share on other sites
StevedTR4A Posted December 15, 2008 Author Report Share Posted December 15, 2008 Mine has a taper on the OD of the aluminium casting for the thermostat housing and it slid off once when I was about a mile from home. So I pushed the hose back on, filled it with water and tried to tighen the clamp. Then I drove back home to work on it. Tightening it encourages it to slide off more. The slippery action of the antifreeze adds to the problem. A cylindrical shape here is better with a lip all around. I cleaned it up and filed the taper even more severely near the end to make my own circular lip all around. Then I put some sealant like you might use to hold the gasket and the two halves together for the thromostat housing, tightened it and let it dry for a day before filling it with a new mix of 50/50 water/antifreeze. It has been fine now for about 5 years. thanks Don. I was wondering whether you could use some type of silicone gasket sealant as you mentioned. I just don't understand why these castings were made with a taper in the first place. Steve Quote Link to post Share on other sites
Don Elliott Posted December 16, 2008 Report Share Posted December 16, 2008 I wouldn't use silicone. That's too slippery and the hose will have a tendancy to still slide off. You need something that will bond without being slippery. Like Permatex Aviation #3 dark brown gasket goo. I think that it's the lip I created that is holding the clamp from slipping down the slope, so it stays secure and the hose stays in place. Quote Link to post Share on other sites
StevedTR4A Posted December 16, 2008 Author Report Share Posted December 16, 2008 I wouldn't use silicone. That's too slippery and the hose will have a tendancy to still slide off. You need something that will bond without being slippery. Like Permatex Aviation #3 dark brown gasket goo. I think that it's the lip I created that is holding the clamp from slipping down the slope, so it stays secure and the hose stays in place. good point Don thanks Steve Quote Link to post Share on other sites
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