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You could still have air trapped in the rear circuit which would give a spongy brake pedal? What's the grip from the rear callipers like? And what condition is the rear brake balance compensator in? If it's seized (especially in rear wheels off the deck) it'll make bleeding harder. You may need to peel back the rubber boot to see if the actuator piston on the compensate is moving and also disconnect it from the rear ARB?

Have you ever been able to lock the front wheels under heavy braking? If not that strongly suggests that there is air in the system somewhere or seals in the master cylinder allowing fluid past the pistons.

Guy

Hi Peter,

Thanks for your response and to answer your questions....

Do I still get air coming through if I re-bleed ? Not sure so I will try this today and report back.

What else has been replaced ? I purchased the car in Jan where the sellers description included "drives like a new car" which was the most appauling mis-description ever....but anyway. As concerns the braking system, the flexi pipes on the front appear to have been renewed and also has new discs and pads on the front. When I bleed any of the front circuits then the fluid flows freely as you would expect. What has always struck me as strange is that the front discs still have all the machining marks from manufacture which suggests to me that the front brakes are just not gripping with any kind of force making the braking performance quite poor. So, my theory is that the air in the front circuits is making the pedal spongy and the front brakes ineffective.

There is also evidence that the previous owner has done something with the calipers as they have been cleaned but it doesnt look lihe the seals have been renewed as the piston seals looks quite old.

There are no fluid leaks from any of the joints throughout the entire system.

Your last question about flushing all the fluid ? Yes twice.

Everything I have done on the car to-date has revealed so many jaw dropping bodges so I think my only cause of action is now to remove the front caliper to see if they are working correctly. The pistons definitely move as they grip the disc enough to stop the wheel from rotating when the pedal is applied.

My best guess at the moment is that there is air trapped in the front calipers somehow.

What do you reckon ?


Cheers,

Steve

Hi Nigel

John originally made a support frame for the original early subframe mounts and then realised the replacement front had different mountings so had to rejig the support frame to suit.

I have not checked, but given he removed the subframes, he was aware of which we needed to have painted.

I will double check tomorrow.

Peter

Hi Peter,
I don't know which subframe you've had coated, but the rear mounting bolt holes
vary between early and late versions.
Early have the bolts screwing into the base of the firewall directly, late type bolt fixings
go into small triangular 'outriggers' that were welded to the outside
of the firewall.
I suggest the subframe is offered up to the car prior to body completion.

(sorry I didn't think of this more recently)

Nigel

One item which I had almost forgotten about was the front subframe which John the body Guy had taken off. It was in decent condition and he sent it off to be powder coated. I picked it up on my last visit. Most likely the only part which will be powder coated, came out very nice. Hard to photograph, but here for the record.

Peter

Hi Steve

I replaced all the brake parts on my Spider when restoring, used a pressure bleeder and simply worked furthest to nearest to MC. Nothing special, it just worked. So I suspect you may have a problem with a seal of flexi pipe. What else have you replaced and if you repeat do you still get any air coming through? I assume you have flushed the old fluid?

Peter

Hi,

Apologies in advance as it seems there is much discussion about this but there seems to be several conflicting procedures for brake bleeding on this forum which are also in conflict with the Haynes manual.
I was hoping that there is a "never fails" procedure that someone can tell me about.

I have just bought a 1982 coupe and I replaced the Master Cylinder to remedy a spongy brake pedal issue. I fully understand that spongy pedal is almost certainly air in the system but had read that spongy pedal is also a possible symptom of a bad MC, so I thought I would replace it anyway. Good job I did as the MC internal bore was rusty and the seals looked scored. Must surely have been the problem for my spongy pedal !!

However, now everything is back together and brakes bled using a pressure bleed apperatus attached to the reservoir (30 psi) and 2 litres of Dot 3. The brake pedal feels exactly the same as it was before.

The bleeding procedure I followed was as per Haynes.......With just the front of the car off the ground, I bled the system in the following order :

1. Front drivers side outermost bleed screw (closest to the disc)
2. Front passanger side outermost
3. Rear driver side (therefore furthest from the Master Cylinder
4. Rear passanger side
5. Front driver side innermost (furthest bleed screw from the disc)
6. Front passanger side innermost

Before fitting the MC, I did attempt to prime it on the bench before fitting.

I would appreciate any suggestions / techniques on how to get stubborn air out of the system

Cheers,

Steve

Is it possible to bleed the MC in situ in case the air is stuck there ?

Thank you both for the pictures and information and to Peter for the phone chat this morning. I'll take a look at Bigg Red to see what's what.

It doesn't seem that long ago that I could get all this sort of stuff, including discs, from Brakes International. Seems very different now.

I pulled the suspension apart to have the rear dampers revalved and replated (by Dampertech who seem to ba Gaz anyway) and to try to devise a way to get more rear braking effort from the rear as the fronts were locking up too easily. I'll leave it to my son now...

Peter

Hi Peter & Peter!

I've just finished the refurb of the rear callipers, you can get an overhaul kit from Big Redd brakes that includes the pistons and all seals including the rubber boot on the end. Leave the callipers attached to the brake hydraulics and remove from the carrier. Put a block of wood in place of the pads both sides and use the brake pedal to move the pistons outa bit, or a lot. Remove from the car, pull the boot off the back, remove the circlip and push/brift/hammer the handbrake lever assembly out. Catch the wedge and spring and unscrew the actuating rod from the back of the calliper. You can then push the old piston out with a drift/hammer. Clean and reassemble. Which is a bastard of a job. There must be a special tool for this.. I used brute force to get the handbrake assembly back in, the piston is pressed down to engage threads and twisted.

Bleed nipples are also at risk of shearing. I soaked mine in release fluid after scraping the crud away for a week and all six came out cleanly. Almost unheard of.

Alternatively, you can ship the whole lot off to Big Redd brakes and they'll do the job for you.

Guy

Hi Peter

First, yes the 1500kb is per total per post on attachments. I use an iPad where you can normally select photo size.

On the rears the piston does just push out, but you need to remove the handbrake assembly which will need to be cleaned etc. Here is a photo of my Spider rears broken down.

One thing Haynes says is not to remove the inner parts from the piston. No idea why it says that and took it completely to bits to clean and have had no issues since reassembling.

If you need any further help, get in touch.

Peter