I am asking this question on behalf of a friend who is an MGB owner and has been unable to find help from the MG community with his problem.
The flexible hose that screws into a front brake callipers is 3/8” x24 tpi (3/8” UNF), the thread on the hose fitting has a male conical end which indicates to me that it should seal on a female cone at the bottom of the 3/8”UNF hole in the calliper. However, the fitting on the end of the hose is too short to seal on the cone. The hose was supplied with copper washers that are larger than the thread diameter and do not look as though they would centralise and form a seal.
I am hoping that there is somebody here who is both a Lotus and MG owner and has resolved this difficulty.
I wondered about using a Dowty bonded washer instead of a copper washer as these washers are available with a centralising ring. My concern with a Dowty washer is not knowing whether the rubber used is compatible with brake fluid.
Did your friend buy the hoses complete with the washers as an assembly, or as two seperate purchases? There should be no sideways movement at the washer (it should be 3/8”) so sounds to me that he might have been supplied with some wrong parts. Or perhaps the hose supplied is designed to fit into a banjo fitting rather than direct into the caliper.
I had an MGB GT: the flexible brake pipe attaches to the calioer with a snug copper wssher and it’s this clamping force that makes the seal not the cone .Tell your mate to get a copoer seal of the correct diameter: best aneal it before fitting to ensure best seal and do this end up tight BEFORE attaching the other end to the hard brake pipe on the mounting bracket..
Thanks for taking the trouble to reply. My friend bought hose and copper washers together the copper washers are slack by maybe 1/16”, this is made worse by the way the thread has been machined down to the minor diameter just under the hexagon where the washer sits.
Since I first posted earlier today I have done some reading about Dowty bonded washers and found that EPDM is the required type of rubber, The Hydraulic Megastore has Dowty bonded washers self centred using EPDM rubber. There is a branch of Hydraulic Megastore at the industrial estate where I used to work, I will see if they have stock and if they will centre on the hose fitting.
Has anyone successfully used EPDM Dowty washers on braking systems?
I would aim to use only anealed copper washers as seals as this is likely to be original fitment. Non OE on safety items like brakes opens a can of worms…
Part of my friends difficulty is the lack of availability of genuine OE components and replicas that are not even a good copy. I completely agree that one does not want to take risks with safety critical components such as brakes.