Braaaakes

[s4mmie]

Thanks for the offer Gav, I managed to meet up with Matt this afternoon on his way home to exchange pads. +1 for GSL's service

Turn's out it in the long run, it wasn't worth my effort...
We gave it a good crack but the old man accidentally popped a rear caliper piston near the end of the install. There's air in the system and I have no fluid.. sad face.

[h100vw]

Got my new pads at 9am, back in the cupboard now for a rainy day...

How did be blow the piston out? I have never seen that. Were you doing the fluid without having the caliper bolted in? That's the only way I can think of doing it.

Gavin

[s4mmie]

Yeah it was all a bit stupid really. The original pads and rotors were wafer thin so the piston was already pretty extended. Coupled with a miscommunication on which way to turn it to screw it back in and pop...

I checked it over this morning and I think there's a verrry tiny leak from the seal. I keep cleaning it and putting pressure through it and there's always a little when I push the boot. It's so little tho that I can't tell if its leaking or remnants of when the piston came out.

What's the side effects of a tiny leak like that? Can I bleed the system now and wait till I get my hands on a second hand caliper?

[h100vw]

Yeah it was all a bit stupid really. The original pads and rotors were wafer thin so the piston was already pretty extended. Coupled with a miscommunication on which way to turn it to screw it back in and pop...

I checked it over this morning and I think there's a verrry tiny leak from the seal. I keep cleaning it and putting pressure through it and there's always a little when I push the boot. It's so little tho that I can't tell if its leaking or remnants of when the piston came out.

What's the side effects of a tiny leak like that? Can I bleed the system now and wait till I get my hands on a second hand caliper?

You'll have to make that call Sam but that's what I would do. You'll feel it in the pedal, if it's going down.

Gavin

[s4mmie]

I think I'll replace it for my peace of mind. If the seal is broken will that introduce air into the system?
The pedal isn't going down now after bleeding, but I still have a crap pedal. I've tried bleeding in both directions, (closest to MC back, furthest to MC forward) and I still can't get all the air out. I'll book it in on Monday to get it bled.

In the meantime I'll keep an eye on the rear caliper and MC fluid...

[h100vw]

Does the pedal get harder with each pump?

If so there'll be air there somewhere. This is my experience.

If you clamp off the flexi to the duff caliper and the pedal improves in feel, then that's where your air is. As long as you have rubber hoses you can do this, don't clamp braided ones obviously.

When you bleed manually, not with constant pressure, you do risk sucking air back in with the vacuum caused by the pedal rising. This is why you need a one way valve in your pipe or to nip the bleed screw each time.

What you need to avoid at all costs, is air going up from the caliper. Bitter experience has shown me that just makes life difficult.

I have had air trapped in calipers and had to take it off the car, put something between the pads and then orientate the caliper to get the bleed screw as high as possible. Tapping the caliper would probably help get any air to the top.

Gavin

[Jmac]

"If you clamp off the flexi to the duff caliper and the pedal improves in feel, then that's where your air is. As long as you have rubber hoses you can do this, don't clamp braided ones obviously." sounds like familiar info
You will still have a crap pedal even with it bled until you have bedded the pads in, then make a judgement on how bad the pedal is. i keep going over this but changing fluid on the 9N is normal way but if you have air and have to "bleed" then the method is altogether different.
Ill post that up later, yes i have said i woyuld already but got more xmas stuff on. Only came on for a sneek peek and thought i would chime in before too much goes astray
All good
Jmac

[s4mmie]

Hey Jimmy, thanks for chipping in mate, I know you're busy
Yeah I thought the new pads would be affecting the situation so I managed to find a nice quiet stretch with plenty of runoff just in case.
I got the new pads bedded in nicely, still a crap pedal. It's to the floor to bring it to a stop.

Here are some symptoms:
The pedal virtually goes to the floor when the car is running and does not get any firmer.
The pedal gets firmer pumping it up when the car is not running.
The engine has a hissy if you pump it in rapid succession, I assume this is just because the booster is pulling so much more vacuum with the pedal going to the floor.

I tried a few tests listed on this forum post and all checked out fine ---
Headache... brakes fading, engine sputtering...!!!...!!!

Could I have air in the ABS pump which is why I can't find it?
Wondering if I should check the check valves or the plastic splitter that comes from the intake manifold to the brake booster. I have a funny feeling there's more noise than I remember coming from around it...


Any suggestions?
If I can't find anything tomorrow I'll have to book it in somewhere.

[Dukzzz]

Hello!

Would the set on ECS fit the 9n polo??

Cheers!

For illustration purposes here are a few shots of the ECS carries for the Porsche calipers on 312mm rotors.

Volkswagen Golf IV 1.8T > Braking > ECS Stage 2 > ES#1170 ECS Big Brake Kit - Stage 2 - Slotted Rotors (312x25) - MK4S2V1BBK-R SLT

For those with a fabrication back ground please comment

[s4mmie]

So all sorted!
Took it down to Stopmasters at Brendale, great blokes.
Got the braided lines fitted and another fluid flush and bleed (not happy with the last mob who did it).
I also got them to stick their head in around the rear caliper to check for any rogue fluid and apparently all good.. so I'll monitor it for a while but I think it's going to be fine.

The pedal is still fairly soft, but it always has been, not personally ideal but there's plenty of braking force available! If I stomp on it fairly rapidly it can lock them up no problems now. Before I had it to the floor and had to wait for it to slow down


What's the difference between Penrites 'SIN' and 'Racing' fluid? They seem virtually identical from the blurbs and specs on the bottle, just different colours? The only other thing I can see is the 'Racing' bottle lists some SAE and AS specs..
<EDIT> Turns out the 'Racing' fluid now supercedes the 'SIN' fluid. I imagine it's essentially the same fluid with some refinements..