badhuis Posted July 17, 2018 Report Share Posted July 17, 2018 Temperature went up - opened the bonnet - saw a top hose pissing down. Nothing to be seen on the outside but there is a huge split in the rubber. Hose was a couple of years old, I replaced an old smooth ribbed rubber example as that was getting old (20+ years). But I did not threw away the old one... so that is fitted now again. Will be buying a new one though. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted July 17, 2018 Report Share Posted July 17, 2018 (edited) Not all top hose are made the same. That failed hose looks like one of the far east remakes from some years ago, that were removed from the market quite quickly; or perhaps a very old stock genuine Unipart GRH453. You say you bought it a couple of years ago - that fits with the far east remake stuff. What radiator pressure cap are you using? NOTE 7 lb pressure is max specified for TR4/4A. Even though you can buy and simply fit an higher rated one (from a '73 on TR6) they may cause problems, unless you have done other precautionary work. An higher pressure radiator cap will just raise the pressure and the boiling point of the water in the cooling system. The belling out of each end of the hose is a visual feature original un-reinforced hoses suffered from. - I have various used samples in that shape. Help Is at Hand - I have been working on this TR2-4A top hose for over a year now. The top hoses are in the throws of being re-manufactured now with stockinette covering, & integral cotton string mesh reinforced EPDM polymer. They look as correct as genuine but are constructed with modern string mesh reinforced EPDM polymer with a stockinette covering that performs better than the original non reinforced natural rubber hose. - Your failed item has no string mesh reinforcer in the 'rubber', which is probably part of the reason it swelled and split. A quantity of the newly re-manufactured hoses are out on continuous test in TR Register member's cars and have been for some months now. No failures of the hoses nor catastrophes have been caused by the hose swelling, splitting or leaking. One car recently boiled in traffic and blew its head gasket, but not because of the re-manufactured hose the car was testing. Just high ambient temperature and the radiator not cooling sufficiently. PM me as I may be able to help. Cheers Peter W PS Here is a prestige classic car parts supplier who hated the junk that was being offered, and inspired me to get the TR 2-4A top hose made correctly. https://www.introcar.co.uk/radiator-bottom-hose-p171 Edited July 17, 2018 by BlueTR3A-5EKT Quote Link to post Share on other sites
Waldi Posted July 18, 2018 Report Share Posted July 18, 2018 Peter, Im often impressed by your knowledge of our parts and the effort you (and your colleagues?) take to improve the parts. Thank you, Waldi Quote Link to post Share on other sites
iain Posted July 18, 2018 Report Share Posted July 18, 2018 Peter What a brilliant initiative, I would be very interested in this product Iain Quote Link to post Share on other sites
badhuis Posted July 18, 2018 Author Report Share Posted July 18, 2018 Many thanks Peter for your detailed answer. PM sent. Quote Link to post Share on other sites
Z320 Posted July 18, 2018 Report Share Posted July 18, 2018 (edited) Hi, I own my TR4A since 9 years. It came with a 13 PSI radiator cap, still fitted, which allows higher preasure and collant temperature - if needed by the situation. Higher temperature gives more cooling power the the radiator. 110 degrees Celsius this summer was no problem on a sunny day, 30 degress C after 1 hour stop and go on the autobahn. Not even any coolant has been blown out in the overflow bottle. I changed all hoses when I bought the car, so this is 9 years ago, suplied from xxxxx . All of them have a texture in between layers of rubber. I see no reason at all to change them now after 9 years. To fit them on the car it is a good idea to put them some minutes in hot water so make them more elastic. The upper hose between thermostat housing and radiator I cut some cm (!) shorter to set it easier in place. I use the oriningal wire clamps, can't count how often I set it in pieces and together again, the connection is always water proof without problrms. Ciao Marco Edited July 18, 2018 by Z320 Quote Link to post Share on other sites
stuart Posted July 18, 2018 Report Share Posted July 18, 2018 We have some of Peters hoses on long term test down here and they have performed faultlessly even in the temperatures encountered lately. Stuart. Quote Link to post Share on other sites
Z320 Posted July 18, 2018 Report Share Posted July 18, 2018 Sorry Peter, I did not realise this is part of your business and did not disturb this. Ciao Marco Quote Link to post Share on other sites
peejay4A Posted July 18, 2018 Report Share Posted July 18, 2018 (edited) I know I have said this before but do not fit a 13 lb cap if you have a bellows type thermostat. 7 lb is as high as you can go. Edited July 18, 2018 by peejay4A Quote Link to post Share on other sites
Waldi Posted July 18, 2018 Report Share Posted July 18, 2018 (edited) Hi Pete, Always eager to learn: can you explain why not? Thanks, Waldi Edited July 18, 2018 by Waldi Quote Link to post Share on other sites
peejay4A Posted July 18, 2018 Report Share Posted July 18, 2018 The bellows cannot overcome the increased pressure and the thermostat will not open, fully or not at all. Quote Link to post Share on other sites
Z320 Posted July 18, 2018 Report Share Posted July 18, 2018 ???? ? Quote Link to post Share on other sites
Waldi Posted July 18, 2018 Report Share Posted July 18, 2018 The bellows cannot overcome the increased pressure and the thermostat will not open, fully or not at all. The increased pressure is throughout the system, so on both (all) sides of the stat. Or is the bellow a sealed area (space) and this will then be compressed more by the static pressure? I have never seen one in real. Thanks, Waldi Quote Link to post Share on other sites
Lebro Posted July 18, 2018 Report Share Posted July 18, 2018 The increased pressure is throughout the system, so on both (all) sides of the stat. Or is the bellow a sealed area (space) and this will then be compressed more by the static pressure? I have never seen one in real. Thanks, Waldi The latter - the bellow is sealed, & contains mainly air with a bit of fluid which vaporises at a certain temperature, & increases the internal pressure, which opens up the bellows to move the valve towards the open position. If the external pressure is excessive, then this will comprimise the working of it. Bob. Quote Link to post Share on other sites
peejay4A Posted July 18, 2018 Report Share Posted July 18, 2018 Thanks Bob. That’s a much better explanation than I could give. Quote Link to post Share on other sites
RogerH Posted July 18, 2018 Report Share Posted July 18, 2018 The hose on my 4A - under test for Pete - has done apprx 4+K miles and doing well. Roger Quote Link to post Share on other sites
Waldi Posted July 18, 2018 Report Share Posted July 18, 2018 Thanks Bob too. Waldi Quote Link to post Share on other sites
BlueTR3A-5EKT Posted July 1, 2020 Report Share Posted July 1, 2020 Update on tests of the remanufactured stockinette covered GRH 453 top hose that Moss are now selling - nothing adverse to report from anyone anywhere in the world. For those who want a real genuine NOS item - Have just spotted someone selling an original top hose 'John Bull' branded (who made them for Triumph) https://www.ebay.co.uk/itm/LEA-FRANCIS-TRIUMPH-RENOWN-TR2-TR3-TR3A-GENUINE-JOHN-BULL-RADIATOR-TOP-HOSE/143599249448?hash=item216f2ea828:g:aCsAAOSwbFFetRnq Cheers Peter W Quote Link to post Share on other sites
stillp Posted July 1, 2020 Report Share Posted July 1, 2020 31 minutes ago, BlueTR3A-5EKT said: Update on tests of the remanufactured stockinette covered GRH 453 top hose that Moss are now selling - nothing adverse to report from anyone anywhere in the world. Another positive here - mine has only done about 1k miles but has been off and back on a couple of times. No sign of deterioration. Pete Quote Link to post Share on other sites
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