Brake upgrade

[vipergts]

Thinking about changing the front callipers and discs but what set up has worked for you guys??

My std set up atm isn’t great but on the second pump they’re not actually that bad though I’m looking for decent brakes from the first pump.

[mgcjag]

If they get better by pumping (second pump)....then something is wrong.....probably air in system....Steve

[vipergts]

Agreed though it’s been bled again and again. Plus the pedal is not spongy.

[mgcjag]

Possibly needs brake overhaul...master/slave/calipers seals etc....Steve

[politeperson]

As Steve says, they may need bleeding.

However, as a heavy brake user, I find changing to a Series 2 set up works for me. No Fade.

[Joes66]

Agreed
Sounds like you need a brake overhaul
You shouldn't have to pump your brakes to make them work better
Joe

[keithmac]

I did eleven bleeds ( in three different ways ) chasing a soft pedal . Turned out to be faulty brand new piston seals. The last thing I would suspect. They had buckled, requiring two pumps to get pressure. Replaced the front pistons in frustration . problem instantly solved. No more double pump to get a hard pedal, brakes work fine , of course EVERYTHING else in the brake system was replaced in the quest to solve this , including the servo twice ( nothing wrong with the first one ! ) disks, master,lines and rears. Finally found it by making a blanking bolt which I could seal off front or rear brakes to isolate which ones where causing the issue. then used the same bolt to isolate left and right ( was both front ).
Good luck with your quest.
Keith

[vipergts]

Thanks Keith.

Sound like expensive fun ;)

[politeperson]

One think worth check on a servo car.

I had one the other day with terrible bakes. Turned out the vacuum connections on the servo were the wrong way round.

This resulted in a lack of servo assistance up to the point the brake pedal was pressed, then the servo tried to reduce the pressure in the system even more!

It also had a vacuum line leak, sending the idle speed all over the place.

Once this was diagnosed, it was a quick fix, the pedal became firm and full braking returned.

You can tell if your servo is working. Press the brake when you start the car and the pedal should move down a bit and firm up.

[vipergts]

Brakes are actually pretty good.

Not the servo but on second pump pedal higher and more efficient

[keithmac]

Oh...bye the bye, the caliper bolts were stretched and bottoming out before the caliper was tight against its bracket. ( suspected older aftermarket bolts ) This did not help matters.
Good hunting !

[mikepday]

If you want really good brakes, (and I know the purists won't be too keen but.....)
I have XJS/XJ12 4 pot callipers on the front with vented discs on a S3 upright, and a steering arm change.
All from WATJAG many years ago. (I'm not sure if the steering arm mod is absolutely necessary)
and....
Rob Beeres Vented rear disc upgrade with S2/3 callipers widened (by Rob) with spacers to accept the vented discs and then pressing on Green stuff pads.
all above with stainless braid teflon hoses and stainless fittings.

The vented rears are probably not really needed unless you're doing lots of hard driving or racing (as I believe Rob devised them for), but if you have any leaks at all from your rear diff output seals it deposits the diff oil on to the inner face of your solid disc leading to a potential heart stopping moment. If you have the vented rear disc the path for the leaky diff oil becomes through the internal vents of the discs which maintains a clean brake surface and your braking efficiency (and clean underwear! )

This of course could also be avoided by replacing the rear diff seals but the temp from the solid discs does tend to allow the oil to seep through even good seals after sustained hard braking (descending through the Alps for example).

the difference in the brakes is like 'Chalk and Cheese' versus the originals, and my wife now feels confident enough to drive the car as the brakes feel like they 'bite' earlier.

[44DHR]

Hi mikepday,
You don’t specify your model of E type, but only the Series 1 E Type Diffs would potentially allow any oil escaping through the rear Diff Output oil seals onto the brake discs, as the later diffs have an “escape passage” cast into the oil seal and bearing retainer flange that allows any oil which has past the seal to run down through a hole in the axle casting.
From a previous post :-
http://forum.etypeuk.com/viewtopic.php? ... 942#p89942

Regards,
Dave

[MarekH]

The vented rears are probably not really needed..... .

If you have the vented rear disc the path for the leaky diff oil becomes through the internal vents of the discs which maintains a clean brake surface and your braking efficiency.

The brakes are much the same but the failure mode is improved.

kind regards
Marek

[mikepday]

Hi 44DHR,

You are of course spot on, it’s a well used ‘66 S1 2+2.

Hi MarekH,

You’re probably right, the largest difference Vs the old setup I can potentially ‘feel’ is a clean disc and a fresh green stuff pad with fresh fluid. But I can now lock all 4 wheels if for some banal reason I chose to, Which was never an option before. The balance front to rear with this setup is also very useable and confidence inspiring.

Mike.

[PeterCrespin]

What pads have you got? I suspect they aren’t bog-standard.

This sounds like a pad problem - too hard a material that doesn’t bite fully until it warms up. The easiest thing is to try a standard compound. Going for a more ‘macho’ spec is often a go faster upgrade that doesn’t improve matters for normal driving. Apart from which, anyone who drives old cars on occasionally wet roads should prefer the standard ‘anti-lock’ setup - i.e. brakes that refuse to lock up unless you absolutely deliberately intend them to skid - which is effectively never.

[mikepday]

Hi Peter.

The original setup had the standard S1 e type pads, but the pistons were just a ‘bit past their best’ and the brakes were frankly shocking, (probably for a multitude of reasons but mostly they were just worn out, as was the car when I acquired it) This was at a time when there few options to overhaul or replace them. So as I was chasing upgrades to the engine I decided to invest in some more ‘reliable stoppers’. They had the added benefit of being cheaper at the time too.

Now I just use standard 4 pot XJ12 Pads at the front and I happen to have a set of ‘Green stuff’ pads on the rear, they seem to bite nicely and are a little more like modern vehicles (which has the added bonus of Supposedly making my wife more confident using them. But I’m willing to bet a pound to a pinch of S##t that it’s entirely psychological in the effect it has to the brake operator in question). However I have put nearly 50000 Miles on this setup and still like it.

The comment about locking is spot on too. I only said/meant I can now lock them if I choose to, and that is effectively never, especially on damper roads.

The quality of the overhauled and new kit available and the slightly more extensive restorations currently being undertaken probably produce brakes of original spec that are much better than when they left they factory.
But as I chose the modification route I am unlikely to revert. I have Kept EVERYTHING I have removed or changed though so the next custodian of the vehicle will have the option. Although I intend to keep it for at least another 50000 miles.
Mike.