brake pipe unions?

craig · #1 25th February 2008, 18:30

All I had left on my brakes is to bleed and test today but while starting to bleed I noticed air escaping from the front 4 way union!!

Upon investigation the union has shallow seats while the marlin supplied hoses have a steap seat angle, I phoned demon twocks and they said all 3 and 4 way unions are the same! Has anyone else had this problem?

When fully tight in the union the pipes have about a 1mm play in them still in the new 4 way union, but not in my marlin supplied 3 way unions which look to have a differant seat

Cheers
Craig

alackofspeed · #2 25th February 2008, 18:39

Can't help with the union problems, but out of interest what drove the need for a 4 way union?

craig · #3 25th February 2008, 18:54

I wanted to try and keep the hoses I already had as they are expensive so just replaced the front 3 way with 4 way....with no servo you only have 1 out line from master cylinder so rear brake line takes 1, 1 feed in and 2x front

with bias in 2x 3 way unions for front

Craig

craig · #4 26th February 2008, 16:58

for some reason I have not been able to get on this site all day??

Anyway I have found out the reason why there is play in my brake pipes!!
All the new unions I have purchased are only threaded 2/3 rds of the way down hence there was no chance of ever sealing the fittings inside the unions

very strange, so either the marlin brake pipes are completely diff to every other supplier or I have had 4 dodgy unions......spoke to demon twocks again today and they assure me 2/3 rds threaded is correct and all brass unions are from the same supplier no matter who you but from

So I have 2 choices either rip out all the marlin supplied stuff and replace at £££'s or try and get the thread tapped further down the union/try and get another union from marlin with full thread

Ric H · #5 26th February 2008, 17:46

Craig,

Others might well correct me here but I thought for SVA you had to have a split system, each part operating on at least 2 wheels, on opposite sides, in which case feeding all wheels from one master outlet would not be accepted. Not sure about the details but you'll find this in the SVA manual section 16.1:

Brakes
16.1*(Braking Systems)
Reasons for Failure
1.
....(stuff cut out here)....
b.
i.A four (or more) wheeled vehicle is not
fitted with a split (dual) circuit service brake
system with each part of the system
operating on at least two wheels (one on
each side).

Anyone know different?

On the subject of the unions, I don't know why they would normally only be threaded 2/3 of the way down... aren't brake pipe nuts usually threaded to the end?? Might be worth ringing a different supplier to check what demon are telling you.

Richard

craig · #6 26th February 2008, 18:23

Rich, glad you posted this but surely I have not changed the setup really as the rover master has 2 feeds from master cylinder but it's all from the same piston??

I will have to check on a road car that has no servo what they have but if that is the case I'm stuffed as you can't buy 2 x outlet masters or I have not come across them

Regards the unions I have had 2 from demon and 2 from europaspares

alackofspeed · #7 26th February 2008, 19:04

Craig, In a standard master cylinder there are 2 pistons.

Ric H · #8 26th February 2008, 19:06

I think standard car cylinders have a tandem piston arrangement - i.e providing two separate pressure outlets (at least when the pedal is depressed). See this link:
http://auto.howstuffworks.com/master-brake.htm
I'd assumed the rover part was similar but with a commoned fluid reservoir inlet.

Tilton do a master cylinder that looks like a tandem (demontweeks sell tilton stuff I think)
http://www.tiltonracing.com/content....ist2&id=22&m=b

Maybe give your local SVA centre a call and check with them?

Richard

craig · #9 26th February 2008, 19:46

Fuck!!

I think something is against me for getting this car registered!! this aside which (hopefully)

although a bitch is just a large monetary setback, but just had a phone call from dash flocking place and my dash has arrived in pieces (3 to be pricise) dont know all the damage yet as he said he is going to try and repair some of it tonight

thanks for link Rich, I had seen that cylinder when I bought mine from demon but did not realise that both ports could be used as outlets

alackofspeed · #10 26th February 2008, 20:23

Well there is a positive buried in there.... at least the dash broke now, when it's not on the car, rather than when it's fitted, and flocked.

craig · #11 26th February 2008, 21:38

John, dash broke by parcel force in transit! claim going in, guy at flocking place said it looks like its been hit really hard as it was packed hideously well

alackofspeed · #12 26th February 2008, 21:46

Arse! I was slightly worried when I sent mine, but thankfully it survived. I boxed mine up to take stupid amounts of abuse - lengths of 2 x 2 strengthening it, and I'd guess the packaging weighed more than the dash!

Hopefully your man will sort it, and you'll be back on track shortly.

I'm definitely going through the early stages of reliability testing with mine - I discovered a broken exhaust mount on Friday. That's now fixed, so the bets are out on what will play up next!

craig · #13 26th February 2008, 21:54

John, the exhaust mounts are very common probs in roadsters like ours! I have read tons of posts about fatigue on mounts from engine moving etc. I dont know wether it will help me but I welded 2 extra ones on when I did mine

Just had an email about dash he has bonded and clamped it but who knows we shall see....it's smashed right over the windscreen channel

BIG_Fella · #14 26th February 2008, 22:15

This is is the company that suppied the hoses http://www.h-e-l.co.uk/
I had the packaging still on mine when i picked them up from marlin with the rest of the kit

craig · #15 26th February 2008, 22:20

hmm I can only see bike applications there maybe that would explain my predicament?? are bike and car unions slightly differant?

Ric H · #16 26th February 2008, 22:48

I dealt with HEL direct to get the end fittings changed on some of my lines to suit the calipers I used. They're very helpful - might be worth giving them a call. They seem to make and fit pretty much every end fitting under the sun...

craig · #17 27th February 2008, 08:49

Quote:

Originally Posted by craig

Fuck!!

thanks for link Rich, I had seen that cylinder when I bought mine from demon but did not realise that both ports could be used as outlets

Just checked and one outlet is a bleed screw, but it looks like the same thread as the main outlet!! Could this be used as an outlet?

craig · #18 27th February 2008, 16:59

Hopefully I'm on my way to getting the master cylinder sorted as the elise unit seems to be pretty much perfect and was designed for non servo.

Bonus of having m10 threads aswell so all I will need to do is fabricate yet another mounting face for yet another master cylinder haha and get 1 more line made up as there are 3 outlets 2x front and 1x rear

Just to try and locate one with reservoir now