Manky's Pop.

[Manky Monkey]

Loony threw together some floor & footwell panels for the last test, held together with self tapping screws. I started trying to adapt them to suit the altered layout, but eventually gave up & decided to start again. So I made a paper template for the footwell panel behind the pedals & cut it out of steel sheet, but by that point it was getting dark & I called it a day.
Terry's back tomorrow, but just when we need him most, Mr Kapri's got transport problems.
I'm fairly confident everything's up to testable standard now -except the brakes -we've still got issues with loss of pedal pressure. If we fail on anything it'll be that & I really don't know what to do about it now.
Time for bed, but it's my day off tomorrow, so I'll be back there in the morning.

[poprodder]

hope your getting on ok andy, i've read else where that kev is having his own major problems.

[Manky Monkey]

Kev's wife's car threw a cam belt, so she's using his Rover estate, but being the star that he is, he managed to resurrect his Mazda to come up to work on my Pop today. I keep saying it, but hope you know I mean it Kev- we'd never have got this far without you mate.
Or Terry. He was already there again when I arrived this morning. We thought we needed another pair of residual valves for the brakes, so I'd stopped off at JackHammer customs in Farnborugh to buy a pair. We didn't need 'em.
This bloody thing's fighting us all the way, but we're so close now.
We keep losing brake pedal pressure- the pedal's fine, then we try it again 5 minutes later & it goes straight to the floor, but after a couple of pumps, is back up again. That suggests air in the system, but we've bled it thoroughly a million times.
Today Kev & Terry got serious, working right through the system from one end to the other, isolating & pressure testing each component. The remote servo's mounted unusually high above the master cylinder, which is under the floor. So that seemed the main culprit. It wasn't. Testing showed it to be working fine. Eventually, after many hours of paddling about in brake fluid, they narrowed the problem down to the front brake calipers. I was originally told they were from a Triumph Herald, but seems they're actually GT6 units. They have 2 pistons, one each side of the disc. They ought to move equally, but the outside ones appear to be stronger than the inboard ones, so that as they move, they push the inside pistons back into their bores. The amount of lost braking pressure equates to the amount of extra pedal travel we're getting. Terry's taken the calipers home to strip down & investigate, while Kev thinks he may have a spare pair we can try.
A couple of accidents along the way -Kev dropped the glass milk bottle full of brake fluid we were using to bleed the brakes -inside the cab. Glass & fluid everywhere, but fortunately no injuries. So we transferred it to a plastic bottle -which Terry promplty kicked over. Oh & I tapped the carb float chamber with a mallet to free the sticking needle jet -& cracked the casing.
Not a particularly successful day, but we're slowly eliminating the possible causes & might have it sussed this time, so I actually feel more hopeful than I did when I arrived this morning.
So first job for me on Monday is to ring "Real Steel" & see if they've got a new front float chamber for a 390cfm Holley carb in stock.
Second job is to phone the test centre & postpone the test. I've spoken to Scottie the hotrod haulier & he's booked up until next week, so if I can, I'll re-book for next Tuesday, the 27th.
In the mean time, I'll carry on with my panel making. As I said, it's fighting us, right down to the wire, but the end's in sight now -thank God.

[poprodder]

andy,
i've a brand new pair of spitfire calipers if you need them to use.
just shout an i'll get them in the post.also new discs as well.

cheers chris.

[cunningplan]

Theres not much difference between the GT6/Spitfire calipers, both of two pistons and the same size. What I was told to do was before your bleed them, push both pistons all the way in (Screw driver/chisel) and then bleed them.
If you do think they are the problem, then you can bleed them the other way. Clamp off one side, pump out the other then clamp that side, open the bleed nipple while pushing the piston fully in, shut the nipple and undo the clamp. try the brake leaving the other one still clamped. If its better, put the clamp back on and then do the same to the other side.
Its worth a try.

[kapri]

Yup, done that Tony, also removed caliper bolts  rotated and tapped calipers. We got loads of air out but no difference to the piston operation. Everything seems to work fine until we actually put pads in and then the inner pistons on both play up .Yet that inner pad is still loose with  0.125" clearance between back of pad and inner piston. Gap only closes as outer piston deflects disc over to touch inner pad.

This is why I thought the brakes were fine having pressure bled them and operated then purely by hand they operate exactly where I'd expect them to for the m/c travel and pedal ratio. It is only when you apply weight by pressing with your foot on them that there is enough pressure to deflect the disc over.

[cunningplan]

I seam to have the opposite, mine are Spitfire calipers and the inner ones seam to stick out holding the brakes on after applying them. Worth trying a diffrent pair if you can just to try it.
One question!! you not using the shims behind the pads are you??? just thought, I had the same problem with the Mini when I fitted shims, I took them out and put copper grease on the backs insted.

[kapri]

No shims, the pads have an antisqueal coating on the back from factory.

[Manky Monkey]

My day off today, so first on my job list was to ring the test centre when they opened at 8am & postpone the test. Whoever answered the phone was very helpful & sympathised when I told him we were having problems & needed more time. I've re-booked for a week's time -Tuesday the 27th at 8am. No charge for postponing either, which was nice. I've checked with Scottie & he's still available to transport the truck there & back -all we need to do now is get it test worthy.
Then I rang Real Steel in Middlesex to see if they had a new carburettor float chamber in stock. They did, so I jumped in the car & headed off around the M25 to Cowley, near Uxbridge. My carb had chrome plated float chambers, but they only had the yellowy silver cadmium plated finish in stock. As long as it works, I don't care -I can always have it nickel plated later. 50 quid, plus another tenner for a new needle valve assembly. I actually bought 2 valves cos it's a vacuum secondary carb, so has 2 float chambers. 70 quid down, but I had the parts to fix the carb & hopefully cure the annoying sticky valve.
Straight back down the M3 to the workshop & I opened up the box to find the new chamber came with the valve already fitted. Poo, that's 10 quid I didn't need to spend then. Shame they didn't point that out in the shop. Ah well, it can go in my bag of spare Holley carb parts.
Loony had started work early this morning -well, early for him anyway, (he ain't a morning person), so was going home early, leaving me to lock up when I left. Not long after I arrived, Uncle Kev pulled in, so while I put the carb back together, he set up his brake pressure testing equipment. He checked the master cylinder again, including comparing it to the spare cylinder on the bench. All seems to work, so we're pretty certain the problem lies in the front calipers.

[Manky Monkey]

We re-fitted the calipers & peered all around them -maybe they weren't sitting square to the discs, or the pads were fouling the caliper mounts? Nope, nothing amiss anywhere. I suggested we try blowing compressed air through them, rather than brake fluid. Hmm, now that's interesting. With the calipers off the car & a piece of scrap metal held between the pads, in place of the disc, after a few blasts into the brake pipe fitting from the air line, the inner piston, which had been the problem one, seemed to work fine, If anything, it was now stronger than the other one. A bit more experimenting & the 2 pistons seem to be working equally well, exerting equal pressure -which is what we want. Could it be that the piston seals are dry, creating a suction effect? Id've thought the hydraulic pressure would overcome that, but maybe not. Still seems strange that both calipers had the same problem on the same piston too. A couple of years of sitting in the workshop, getting covered in grinding dust probably hasn't helped.
So Kev's taken the calipers home to strip down, thoroughly clean & lubricate. He has a spare master cylinder, so can bench test them before we re-fit them. With time ticking away worryingly fast, let's hope we've pin-pointed the problem now. See-I can think clever too!
As always, thanks for your time again today Mr K.

[poprodder]

my offer still stands andy if you need them.

[Manky Monkey]

Not sure of the mounting bolt measurements off the top of my head, so don't know if they're a straight fit for the GT6 ones we've got. Waiting for word from Kev about mine, but appreciate the offer Chris & will take you up on it if necessary. 

[cunningplan]

according to this http://www.lotuselan.net/forums/elan-f15/gt6-brakes-revisited-t19846.html GT6 calipers have a 3.50" spacing

[Manky Monkey]

Okey doke. Thanks Tony.

[spanners]

according to this http://www.lotuselan.net/forums/elan-f15/gt6-brakes-revisited-t19846.html GT6 calipers have a 3.50" spacing
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i just had a look though that and its made me ,,cry,, i.v,e thrown £1000.s away