84 replies to this topic

[Hexxeh]

Is it using all braided hoses rather than hard lines with braided to calipers that's causing the issue? It's maybe finding a weak spot on the diagonal hose that's reducing pressure to that caliper?

 

Possibly? Though if anything I'd expect that to make the passenger side weaker, not stronger?

 

Have you bedded in the new pads and discs properly?

New calipers can also have slightly sticky pistons that haven’t found their ideal resting position yet and perhaps one is taking more travel to contact the disc. You should be able to inspect the pads & see if they have much wiggle room at rest, and then observe how they contact the disc when someone presses the pedal down

 

I haven't done anything particularly special, just did a few firm but not super hard stops to check all seemed ok.

 

I popped both front wheels off again today before I headed out to my first meet. Checked each piston individually on both calipers, all four each side move ok. Swapped the pads side to side, made no difference. Only thing I did notice is that if I spin the hub on the bad side, it's perfectly smooth. If I spin the hub on the bad side, the pads "knock" back and forth slightly as it contacts them. My first thought is that perhaps somehow the disc is very slightly not true and so that side grabs more, but I'm not really sure how to check. I guess mount a DTI up somewhere on the suspension and then see how the reading changes as I spin the wheel? I guess I could swap the discs side to side, gotta find that seating washer for that though...

Edited by Hexxeh, 11 August 2025 - 08:48 PM.

[Hexxeh]

Mini Sport came back to me, basically suggested swapping the calipers side to side (bleeding off the disc to account for the fact the bleed nipple would be at the wrong side), and then if the bad side doesn't move, try swapping the discs. I'd already tried swapping the pads. If neither of those moves the bad side, it must be the flexi or t-piece/banjo. Bit of a faff but I suppose it will narrow down what the issue is without buying any new bits.

[Hexxeh]

Swapped the calipers (holding off the disc the bleed nipple up to bleed), no change, still pulls left when braking. I can't find the flat washer to seat the bearings again if I swap the discs, but I really can't see it being the disc itself... I think it has to be the hose or banjo bolt at this point?

 

The fact the hose around the subframe is a braided flexi couldn't cause the driver side to be weaker, could it?

Edited by Hexxeh, 14 August 2025 - 06:59 PM.

[stuart bowes]

I would say that's possible yeah, previously you had the solid lines which meant the flexis were the same length at each end.  but now you've got one about 8" long and one about 40" long

 

I don't know a lot about fluid dynamics or anything but gut feeling it's possible the longer side would 'absorb' more of the fluid and leave the shorter one lacking, something to do with the path of least resistance or something .. maybe

 

have you still got the old pipework to hand?

Edited by stuart bowes, 14 August 2025 - 07:31 PM.

[Hexxeh]

I would say that's possible yeah, previously you had the solid lines which meant the flexis were the same length at each end.  but now you've got one about 8" long and one about 40" long

 

have you still got the old pipework to hand?

 

No, long since binned unfortunately.

 

Just noticed HEL actually sell a kit that does exactly this: https://auto.helperf...nt-subframe-kit

 

You'd hope they wouldn't sell it if it caused such a dangerous imbalance?

[imack]

I'd have to swap the discs left to right to eliminate them being the issue. Back in the day when we were replacing front drums on minis, it wouldn't be unusual to have to swap ew drums from one side to the other to eliminate brake unbalance.
I've never used a flat washer to seat taper bearings and never had a problem.

[stuart bowes]

who knows.. as I say I'm no expert or anything, but once you've tried everything else it starts to look that way doesn't it

 

it could be that the HEL ones are made more rigid in comparison to more standard flexi hose

 

I guess after the discs start with the banjo bolt and check there's no blockage or anything but presumably it all bled through ok?

Edited by stuart bowes, 14 August 2025 - 07:50 PM.

[Hexxeh]

 

 

who knows.. as I say I'm no expert or anything, but once you've tried everything else it starts to look that way doesn't it

 

it could be that the HEL ones are made more rigid in comparison to more standard flexi hose

 

I guess after the discs start with the banjo bolt and check there's no blockage or anything but presumably it all bled through ok?

 

Yeah all bled through just fine.

 

I'd have to swap the discs left to right to eliminate them being the issue. Back in the day when we were replacing front drums on minis, it wouldn't be unusual to have to swap ew drums from one side to the other to eliminate brake unbalance.
I've never used a flat washer to seat taper bearings and never had a problem.

 

I need to re-bleed again to swap the calipers back, so I think I'll pick up another hose and banjo bolt tomorrow from Mini Sport and swap those at the same time, and if it's still persisting, try swapping the discs. I don't really want to run the risk of knackering a fresh set of timkens not using the flat washer, so I'll get one of those tomorrow too just in case.

Edited by Hexxeh, 14 August 2025 - 07:58 PM.

[Hexxeh]

Had a good dig through the tool drawers and found my flat seating washer, so tried swapping discs side to side. Still no difference, pulls to the left as before.

 

Feels like the only things like must be the hose and the banjo bolt... unfortunately Mini Sports site says they're completely out of front braided hoses. It has been wrong before though, so I'll give them a call in the morning.

 

I did a bit of research, it seems like the long flexi around the subframe would make the passenger brake slightly less responsive (because of the slight expansion of the braided line) but with a braided line it's very minimal compared to rubber. In any case, that'd be the opposite to the problem I have, where the driver side is the weaker one.

[Hexxeh]

Went to Mini Sport today and got another set of braided hoses (the front pairs were out of stock, so had to buy a full new set of four...) and another banjo bolt and pair of washers for it.

 

Fitted up tonight and... it seems to have sorted it! I can press on hard enough now to lock the wheels without it trying to throw me into the kerb. It seems the hose itself was faulty from new somehow. I noticed the caliper side fitting is slightly larger (9/16" AF rather than 1/2" AF) so I'll swap the passenger side over too just so they match.

 

I'd dropped the adjustable pressure limiter for the rears right down to rule them out before, so now each time I go out I'll keep tweaking that until I get the rears dialed in.

 

Glad to have the car in a state where I can start to drive and enjoy it at last! As always a few things I need to tweak and sort, but nothing that stops it being used in the meantime.