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Brake Hose Confusion
stephen_gusterson - 16/9/03 at 09:30 AM

Thought id ask a question or two here before I go back to Merlin Motorsport to see why after 2 attempts I cant get brake pipes that fit!

I am using granada ABS front calipers. I'm reasonably confident they are the same as the non ABS sierra of the time.


The hose fitment to the caliper, looking inside it, appears to have a concave 'well' which you would normally expect a covex (pointy) end to seat into.

I am 110% sure that a convex fitting, with an angled outside edge, goes into here. I know this cos I have the original hoses, and new standard hoses (way too short) that have this fitting. looks dodgy, but thats whats fitted. So I seem to have a convex caliper that needs a convex hose fitting with a chamfered outer edge.

Asked Merlin to make up hoses to longer length using braided (thats all thats on offer) hose and plarted fittings. Back came hoses with the same end each end - ie, the pointy convex end like that which fits the copper pipe on the car body. Didnt look right, and in any case, didnt seem to tread in far enougth to seat in the caliper. Even though the convex profile looks better proposition than the original concave one.

Send hoses back, with a brand new original sample hose to copy the end of.

What I got back today still seems to be wrong!

I now have a convex end fitted. But. It looks about 2mm shorter, which I dont think will seat, and the convex area, which should have a chamfer on the outside edge, doesnt. It looks great to fit to a single flare copper end, but I dont think either of the ends I have been supplied so far are in any way right.

Before I ring up Merlin and thry a third time, I wonder what others experiences are getting these hoses made, and what ends to use. The std Ford concave to a concave fitting with a small external chamfer looks wrong...........

help.

atb

steve

]

[Edited on 16/9/03 by stephen_gusterson]


David Jenkins - 16/9/03 at 09:38 AM

I had a similar dilemma with my Cortina uprights. I have seen many flexible brake pipes fitted directly into the caliper hole, but I was never happy with that as it wasn't the way it was designed to be used. Originally my calipers used a short length of rigid brake pipe with double cone ends. The flexible pipe fastened to the end of this pipe, supported by a bracket (which also locked the caliper mounting bolts).

In the end I decided to reproduce this on my calipers, and I'm very happy with the results. DISCLAIMER: I know many people do it the other way, and it works just fine - I'm just fussy!

Incidentally, I got my flexibles from Think Auto - nicely made, cheaper than elsewhere, and the braid is plastic-covered, so no abrasion problems. You can even get the covering in assorted colours!

cheers,

David


stephen_gusterson - 16/9/03 at 09:52 AM

Thanks David. One of your posts originally said you might use Merlin. Perhaps a bummer non-recommendation

I do have 2 copper washers with the hoses.......so this does kinda tie in with your 'direct into the hole' experience. It doesnt seem right to use copper washers as a seal when there seems to be a seat in the caliper for a proper fitting.

Will see if I can post pictures later....

atb

steve


loafersmate - 16/9/03 at 10:11 AM

The copper washers are normally only used with banjo fittings where the hose has a circular end with a hole in it and the fixing bolt has a hole up the centre and then a radial one at the end to connect up the oil. The hose is then 90 deg to the caliper hole axis.

Ben


David Jenkins - 16/9/03 at 10:14 AM

I was planning to use Merlin, as they seemed to be a 'customer-friendly' organisation. However, I then discovered 'Think Auto' while looking for other things...

My worry about going direct into the caliper is that the hole doesn't have a machined ring around the hole to seat upon - it's fairly smooth, but nowhere near flat in an engineering sense.

rgds,

David


stephen_gusterson - 16/9/03 at 09:02 PM

Actually, David, my caliper does seem to have a recessed ring around the caliper fitting - although its pretty crudded up. I dont have any washers on the original hoses (which I hacksawed off the car!) and I dont recall if any were ever fitted.

It just seems whacky to have tapered fittings all over the car, and then have just a copper washer on the caliper.....

more suggestions anyone - im still confused!

atb
steve


Rorty - 17/9/03 at 05:27 AM

Steve, the hose-ends you need for your caliper are male flares (though probably (metric?) not SAE 45 degree flares), and do bottom out on the tapered seat in the calipers.
A shorter hose-end with a copper washer is no substitute for a seal between two tapers.

Sorry, I meant to give you the part numbers.
3/8 UNF #HETX1-3
M10 x 1.0 #HETX2-31

[Edited on 17/9/03 by Rorty]


Dick Axtell - 18/9/03 at 07:54 AM

Hi Steve,

Uh-oh!! Being described as an expert is usually the "kiss of death". However, yes I have accumulated experience on brakes, (development & design), and associated systems. ABS was another, specialist area, which I did NOT cover (the preserve of software engineers).

Quote: "The hose fitment to the caliper, looking inside it, appears to have a concave 'well' which you would normally expect a convex (pointy) end to seat into." /unquote.

Correct. Loafersmate has also made the point about copper washers, and Rorty went back to basic principles re "taper" seals. For any banjo connection, spot-faced ports are essential.

BTW - the standardised Euro (female) brake port has a 120deg. cone angle.

IIRC the usual hydraulic connection for Cortina/Capri/Excort calipers was via a short length of bundy. This was mounted between the caliper and a caliper-mounted bracket, with the long male end of the hose attached to it.

If you're connecting the hose directly to th caliper, follow Rorty's advice.

Good luck with that build


stephen_gusterson - 19/9/03 at 10:11 PM

thanks all for the help!

I have spoken again to Merlin Motorsport, who seem nice helpful guys.

They are having a third go at making up the right end for the caliper!

This time, they looked it up in the goodridge book - and the fitting they said is used isnt the std ford one - which is a concave fitting with an external taper, going into a concave taper.

They say it should be a convex one on the pipe. I hope the third attempt is right. At leat this one has a longer thread so it shouldnt bottom out on the threads before the tapers engage......

Also, the end thats being fitted would be compatible with the 'bundy tubing from the caliper' approach, as a fallback solution.

atb

steve

[Edited on 19/9/03 by stephen_gusterson]


JoelP - 19/9/03 at 10:26 PM

all these thing i have to look forward to...

bag o shite innit?


stephen_gusterson - 19/9/03 at 10:45 PM

quote:
Originally posted by JoelP
all these thing i have to look forward to...

bag o shite innit?


Just a bit, at times.

The little things trip you up.

One thing I keep in mind is that every little nut bolt switch wire every bloody thing has to be put there by me.

I thought brake pipes would be straight forward - specially as they are just longer std granada ones, but nooooo.....!

atb

steve


JoelP - 19/9/03 at 11:05 PM

My stumbling block will be the coolant system, havent even worked out where the thermostat is yet! some fun posts coming up in 3 or 4 months time!