Technical replacing flexi brake pipe

[mikejt]

Was just wondering, what tools are needed to replace this? is it screwed on

its the front flexi pipe that goes from the metal pipe to the brake caliper...

it cracked on me when i was doing 70 coming off the motorway towards traffic!!

i was lucky the lights changed to green and the 3 cars in front got out the way in time as there was no way i was stopping!!!

 

[MikeSalt]

It is advised to get a proper brake hose spanner, since they are a weird size and tend to round off with normal sizes. At the caliper side, remove the caliper from the hub, loosen the hose from the caliper, but once slack, rotate the caliper, not the hose (unclip any pad wear wires first of course). At the other end of the hose, I think you have to slacken them from the rigid hose side, and then pull the clip off to free the hose from the bracket. These clips usually get so rusty, that it is worth getting new ones to refit your new brake hose.

Assembly is the reverse, first reattach to the top, and then screw the caliper back onto the hose (rotating the caliper, not twisting the hose). Of course, bleeding will be necessary on this corner after this work, so a brake bleed kit will also be required. If you cannot get a willing assistant, there are one-man brake kits too.

 

[mikejt]

Thanks for your reply!

is it just that corner that will need bleeding? or is it best to do all 4 just to be safe? i have lost near enough all of my fluid, just wondering if me repeatedly pressing the brake hoping it would work could have let air in the sysyem and circulated round a bit?

so the only specialist tools i need are a brake hose spanner and bleeding kit?

 

[DaveMcT]

One hose has failed so it would be a really good idea to change them all. Put another way - I wouldn't take the risk.

You will need a special spanner to refit the captive nuts on the ends of the metal hoses. But the old hoses can be removed with sockets and molegrips. The retaining nuts on the hose ends are very thin. You might have to grind the end off a socket to remove the internal champher. Ideally use a 6 point socket.

1) To stop it pulling in air, put some cling film under the brake fluid cap.

2) Find some small bore rubber hose cut a 2" length and plug one end of the hose. Clean off all spilled fluid before it strips the paint.

3) Using the flare nut spanner and holding the old hose ferule with a hose grip, unscrew the flare nut. Its likely to be tight. Don't worry about messing-up the ferule.

4) Use the hose you made up cap off the end of the metal pipe.

5) Take the old hose off the chassis and then unscrew it from the brake caliper. Lots of easing fluid will help as the backing nut is all too easy to round-off. If necessary cut the old hose.

6) Make sure the caliper hole is clean and fit the new hose with some good quality anti seize paste.

7) When you bolt the hose to the chassis be careful the flexible isnt twisted - Important with rubber hose - Imperative with braided stainless hose. If the chassis bracket is broken or rusted you must fit a new one. Welded or bolted to the chassis. If not the metal brake pipe will vibrate and soon be cracked.

8) Remove your rubber cap and reconnect the flare nut. Be careful the flexible hose doesn't twist as you tighten it up.

9) You could now bleed this brake and move on to replace the next hose. Probably less hassle than bleeding them all at the same time.

10) Repeat on all hoses and then rebleed all brakes. The pedal should feel firm.

 

[MikeSalt]

In that case, bleed the whole system (start furthest from master cylinder, working closer to it).

One other thing you might need is a crow's foot adapter if you want to accurately set the torque on the hose joints. Now I have no idea what torque it should be, but it's 17Nm for an M10 thread on AP Racing calipers. Shouldn't imagine it to be too different for the Punto calipers. Don't forget to use an appropriate calculation to convert your crow's foot adapted torque setting.

Also, a spare car will be useful just in case the rigid hose disintegrates when you remove it, or the caliper gets damaged in the process.

 

[DaveMcT]

Good point Mike.

Before you start, get under the car and check out all of the metal hoses. Look very close around the flare nuts. If any are rusty you would perhaps be best having new pipes and hoses done by a professional.
Rusty brake pipe = MOT failure.

 

[MikeSalt]

One hose has failed so it would be a really good idea to change them all. Put another way - I wouldn't take the risk.

And indeed that is a good point by WhiteSei. I would definitely replace both the front hoses at least. These are very vulnerable to damage when the caliper is taken off and not supported properly. I wouldn't put it past some garages to try to unscrew the hose from the caliper without removing the caliper, thus twisting the hose to the point of internal collapse.

 

[mikejt]

Thank you both for your help, i will definatly do both sides seeing as im replacing the fluid anyway!! my car was only MOT'd last month and nothing was mentioned about the brake lines, i will have another look but as far as im aware, its just the rubber hose thats a problem, the brake lines actually look newer than the car to me (from when i was looking under the car at something else a few months back)

 

[DaveMcT]

The metal lines are plastic coated so should be good, but any damage to the coating and they will rot like there's no tomorrow. The clutch line isn't coated and tucks behind the gearbox mounting where it rusts away quietly. Not good because access is terrible.

While you have it apart its best to do all the flexibles. Even though you know that last one still needs doing - its out of sight out of mind...

If the discs and pads look a bit iffy you might choose to do them as well. They are very reasonable prices (compared to bikes anyway).

 

[mikejt]

theres plenty left in the pads and disks, but would you reccomend changing them if any brake fluid has got on them? or would they be ok?

and are there only 2 flexis? or 4 (2 front/2 back), or are there more than that?

i will let you know how i get on tomorrow, i may be back for more advice, hopefully i will be alright though

 

[MikeSalt]

Any contamination of the brake pads cannot be satisfactorily cleaned off, so you would need new pads. Probably a good idea to take the pads out first before disconnecting the caliper (unless they are already trashed from the initial leak). The discs you can just clean with brake cleaner.

If you have drum brakes, then there are only four flexis, two at the front, and two between the rear subframe and trailing-arm/torsion-beam (mk1/mk2). The ones at the rear don't get nearly so much abuse because the rear suspension is not replaced as often as front brake pads, so it's up to you. If you have disc brakes at the back, then there would be six hoses (and extra pair from the arm to the caliper)

 

[westfielder]

Some excellent advice above – would like to add some bits tomake it really simple to understand for other novices like me…

YOU DO NOT NEED TOREMOVE THE BRAKE CALIPER

What you need:
New brake pipe = best to replace both
Suitable brake fluid – see driver handbook, I reckon I used50ml max of brake fluid for doing 2 sides
Small piece of rubber tubing as listed above in earlier post(could use the link piece from a bleeding kit)
Brake union spanner – it’s a tad smaller than 11mm
Rags
Plusgas or some other spray or penetrating oil that assiststo loosen frozen nuts
14mm open jaw spanner
Grips
A bowl
Some spirit cleaner
A small wire brush and an old toothbrush
Copperease or similar
Jack(s)
Axel stands
Wheel spanner
Pair of pliers

1. Park

2. Leave in 1st gear

3. Handbrake on

4. Bonnet up

5. Top up the brake fluid reservoir then put asingle piece of soft plastic bag (not super market carrier) across the top andput the lid back on.

6. Chock rear wheels

7. Loosen front wheel nuts

8. Jack up front and apply axel stands – I leavejacks in place as a safety feature

9. Remove road wheel

10. Note the routing of the flexihose especiallywhich way it loops back on itself – take a pic with your phone

11. Clean road dirt from around both ends of pipeand above the pipe in the wheel arch so dirt doesn’t drop in onto brake fluidpaths – you don’t want even one grain of dirt in the fluid. Caution – will containbrake dust so don’t breath it.

12. Use wire brush to clean carefully around bothends of the flexihose – don’t brush too vigorously around the metal break pipeas you want to leave the coating on it. Caution – will contain brake dust sodon’t breath it.

13. Now use solvent cleaner and toothbrush to cleanaround the two ends of the flexihose too then wipe away excess. Caution –ideallydon’t get on brake disks

14. Squirt plusgas on the union at the end of the metalpipe give the metal pipe some gentle taps with a hard plastic object (carefulof the coating)

15. Wait 10 mins

16. Apply more plusgas. Caution –ideally don’t geton brake disks

17. Wait 10 mins

Description of the mountings:

The bottom end of the flexihose just screwsdirectly into the brake calliper. The top end pokes up through a 1” wide horizontalflat metal plate with a hole in the middle mounted on the wheel arch and issecured just with a pull-off retaining clip. The metal brake pipe from abovehas a standard brake union that inserts into the top end of the flexi pipe withthe union nut tightening to the flexihose top. Apart from the pull off clip, thejunction of the two pipes effectively hangs in mid air.

18. Gently try to undo the union nut of the metalbrake pipe. Use plenty of light so you can see to make sure that the metal pipeDOES NOT Rotate. The danger is that squished end of the pipe under the nut thatmakes the union will stay attached to the nut and twist off the end of the softmetal pipe – if that happens you’ll have to replace the whole metal brake line.If it won’t undo – more tapping and more plusgas. Mine did unto quite easilywith an 11mm open jaw spanner – but I was about to give up and go and buy aproper union spanner as I reckon I was about to round off the nut (it’s only brass I think)

19. Once it starts to loosen nip it up again, removethe metal clip that secures the top of the flexihose to the horizontal metal plate by tapping itsideways in rotating action to loosen any rust joint then pull horizontally awayfrom the bracket using pliers. Hopefully the amount of plusgas you’ve used willhave assisted to break any rust joints.

20. Pull the clip off the similar metal plate theholds the middle of the flexihose to the shocker end. Clean it now ready forreuse and clean around the seating where it came from

21. Push the flexihose middle rubber mount off thehorizontal plate so it hangs free

22. Use the 14mm spanner to loosen the flexihose to calliperjoint.

23. Get new pipe unwrapped ready having firstchecked it’s the right one

24. Put the catch bowl on the ground under theworking area

25. Now undo fully the union joint at the top of theflexihose and draw the flexihose down through the horizontal metal plate.

26. Cap off the end of the metal brake line with thepiece of rubber you prepared as advised in the previous post as it will bedripping by now.

27. Loosen the calliper end of the pipe

28. Rotate the whole pipe to unscrew it from the calliper

29. Double check to make sure the surroundingsurface of the calliper is clean – if not clean with outward motion only

30. Insert and screw in new flexihose

31. Twist the pipe to make the loop as per yourphone pic then push the top end up through the horizontal mounting plate andfinger tighten on the brake line

32. Secure the top end of the flexihose with theretaining clip

33. Push the rubber midway bung into the shockerbracket and reattach the retaining clip

34. Tighten the union nut at the top (don’t use toomuch force or you’ll strip the nut thread)

35. Tighten the flexihose bottom end into the calliper.

36. Wipe off all excess brake fluid that’s drippedaround the place

37. Remove polythene bag from fluid reservoir andtop up if required ready for bleeding

38. Bleed the brakes as described all over Youtube andthe web.

39. Wait 20 mins and check for leaks – your pipesshould still be dry

40. Replace road wheel

41. Tighten wheel nuts using some copperease orsimilar

42. Unchock rear wheels

43. Retest brake pedal

44. Go for careful test drive taking tools andmobile phone with you.

 

[Ziggy122]

Oh if you were only 3 years earlier my friend!

Ziggy

 

[fingers99]

:yeahthat:

I'm surprised, in passing, that no-one recommended braided stainless flexis.............

 

[Ziggy122]

:yeahthat:

I'm surprised, in passing, that no-one recommended braided stainless flexis.............

Have to ask why?
If its failed after say 6 years - a Standard one will do another 6 years IF installed correctly, the car will probably be in a better place by then
So why waste money on braided versions?

Ziggy

 

[fingers99]

Better feel and they're not hugely expensive in comparison.

 

[atom0007]

Oh if you were only 3 years earlier my friend!

Ziggy

Still,a cut and paste would make a useful guide!

 

[Ziggy122]

Still,a cut and paste would make a useful guide!

True

ziggy