Bled the brakes, now even worse...

[Ian Lockwood]

My brakes were not as good as they could be post-Bedford trackday, so I thought I'd change the fluid for Castrol SRF to avoid that happening again.

The first thing I discovered was that it's rather tricky to loosen the bleed nipples, as there isn't much space around the nut to fit an 11mm spanner. Anyway, I was using an Eezi-Bleed kit (just the non-return valve into a canister, not the pressure thing you can attach to the fluid reservoir) and as a result of the nipple sitting so snugly recessed in the caliper, couldn't apply the collar that normally clips the hose in place on the nipple. I didn't think that mattered, as the rubber hose of the Eezi-Bleed was hard enough to fit on anyway, i.e. pretty darn tight.

So, got the missus to pump the brakes as I watched the fluid come out, kept the reservoir topped up above minimum, tightened the nut and moved on to the next caliper. Repeat. However, not too long after starting the first caliper (OSR), the pedal started making a "squish" sound, like air was being dragged in or pushed out when depressed. There was no sign of air coming out of the calipers though.

So, finished the job and took the car up the road. Oh dear. Hardly any stopping power over 10mph. Check each caliper - slight leak out of OSR, looked like the nipple wasn't quite tight enough - although I could only manage a very slight further tightening. Took the car out again, still as awful, but no more fluid out of the OSR caliper.

So, £41 of SRF fluid later, I have terrible brakes and will need to bleed the whole system again.

But am I missing something? There was no air in the system to start with and I can't see how it would get in. Could air get in around the thread of the bleed nipples? I've never had that before. Could it get in around the hose, even when it was very tight (but didn't have the collar on)? Most importantly, why does the air sound come from the pedal!?

Any experiences to share would be appreciated. Next step unless I hear otherwise is to do it again, this time using the pressure cap on the reservoir to push it through. I suspect I'll need more than the 1 litre of SRF for that though (gulp!)

[ramjet]

I know that on my Esprit, the factory have set out a definite procedure when bleeding. Have they done the same for the V6?

[alias23]

Hi Ian, unfortunately I don't have a solution however could suggest you call Dan at HPE Auto who are based in Bromsgrove.

Dan is a pretty helpful chap, and generally always happy to help fellow lotus owners with questions when they're in 'need help' mode.

He's also well versed with the v6 procedure as he's done mine plenty of times so may be able to highlight a gap in what your doing which may be resulting in the issues your experiencing.

[Bibs]

12 hours ago, Ian Lockwood said:

Could air get in around the thread of the bleed nipples?

Definitely, in fact given the chance, it would suck in air rather than fluid due to the viscosity.

Also, there's a correct order to bleed the brakes, from the longest line to the shortest. On my Elise, it's LR, RR, LF, RF. 

[Chrisc]

Personally i would get a proper pressure bleeder, and then your not risking killing the master cylinder either. I bled mine a couple of weeks ago, and so easy with the proper bleeder. Just pump it up and then work as you would do normally. Using the brake pedal method is very time consuming, and get it wromg and you will just get lots of air trapped.

get one of these!

http://www.toolstop.co.uk/index.php?option=shop&page=shop.product_details&product_id=10142&l=uk&utm_source=google&utm_medium=base&gclid=CK2GuMPUnc8CFSEz0wodOW0HNA

[Hangar 111]

There is no particular reason why using the traditional method will not give you a good pedal.  It is possible that air has been drawn in, so use of a pressure bleeder does help to prevent this.  Depending on what is being done, we use a combination of methods, as sometimes just pressure will not move air pockets, where pumping the pedal will.

Also there is a guided routine using Lotus TechCentre to bleed the ABS system on the car - this powers up the ABS pump and opens and closes valves, whilst the pedal is pumped and bleed screws are opened.

Dave

[Ian Lockwood]

Thanks guys. I believe the correct order is the same as Bibs stated? It looks like it should be anyway, as usually you start with the wheel farthest from the reservoir and as it's on the driver side, RF last looks correct.

I will definitely be using a pressure bleeder this time! I will open the bleed nipples the absolute minimum I can too.

Imran, thanks for pointing me to Dan, I may well get in touch with him before I attempt this again!

[MartynB]

• Cover all nearby paint work with plastic sheeting before you start.
• Have a bucket of water at the ready.
• Test pressurise before adding fluid to the pressure bleeder.
• Buy a Sealey VS820 (as per link) or similar, not a Gunson EasiExplosion.
• Don't ask me how I know

#PaintIsSoMuchNicerOnTheCarThanTheFloor

[Ian Lockwood]

So, bled the brakes again under pressure (Eezi-bleed job, not pumping the pedal). No air came out of any caliper that I could see.

The pedal still makes a "swish" noise when depressed and the brakes are not what they could be, although not as bad as the first time. I wouldn't say the pedal feels spongy.

The question then is: Was the fluid actually OK and it's the pads that have gone (even though they look OK on visual inspection)?

And secondly, why does my brake pedal now make an airy "swish" noise!?

[Chrisc]

Do you do the inner bleed nipper first on each caliper? Then the outer?

[Ian Lockwood]

There's an inner bleed nipple!? Can't see one on the diagram: http://deroure.com/diagrams.asp?TBL=6248&MAK=1&MDL=40&SMA=0&SMO=0&ST=&SC=0

However, I can see they sell spares as 8 per car, so I guess there are inner ones: http://www.deroure.com/partinfo.asp?MAK=1&MDL=10&TBL=918&SMA=0&SMO=0&ST=A132J6058S&SC=1&PBID=247221

That could explain a lot... I presume it should be inner first then?

Guess what I'll be doing this afternoon...

[Chrisc]

Haha there you go! So many miss them! But yes, multiple pistons, so two bleed nipples per caliper. Inner first, then outer 

[Ian Lockwood]

Fingers crossed that sorts it then. Still not sure how that makes for a "swishy" pedal if the air is in the calipers, hopefully it's just one of those things...

[Chrisc]

All good now?

[Ian Lockwood]

Well, I decided to take the car out properly to see what it's like at higher speed (I only drove it up the road before). It seems the "swish" is actually just the pedal hitting the end of it's travel when you push all the way down when stationary - it doesn't happen whilst actually driving, because braking that hard is lock-up territory. Explains why I've never heard it before!

The brakes are actually OK, just not as good as they were, which makes me think it might be pads. I did notice a little bit of grabbing from one side or the other at the front (i.e. happened slightly on either side), which I suspect may also be worn pads?

I've got to drive down to Hofmann's next week to get my Nitrons fitted, so I'll take new pads and fluid down and ask them to take a look and do what they think necessary to get the brakes back to 100%. Hopefully it will just be a bit more bleeding as there's quite a bit of meat left on the pads.

I would do another bleed myself, but I don't really have the time before it's due at Hofmann's and I've got through almost two bottles of SRF already, so this time it needs to be right as I don't want to use more than the three bottles I've already have to buy!

[Chrisc]

If it's in anyway, then makes sense to let Hofmanns do it. There almost certainly will be a bit of air in each, but as you say, no point in wasting more fluid if it's getting done anyway.