Jack Webb big brakes

32 posts / 0 new
Last post
timb2117
timb2117's picture
Offline
Last seen: 23 hours 12 min ago
Joined: 26/04/2020
Jack Webb big brakes

Just thought I'd share fitting of Jack Webb big brake kit to an imperial sv roadsport. I chose them after advice on the forum and Caterham were struggling at the time with Covid supply chain.

Supply was super fast and email response likewise from Jack - V helpful - only thing I needed extra was part number 77209f braided lines from caterham (wish I'd known at time as I would have ordered together.)

Took hub off and re greased bearings too took about 2 hours per side including a major clean up- one hassle was the copper sealing washer for caliper end was a touch big and off centre so didn't seal first time I bulked the thread up with a bit of PTFE tape so it centred perfectly and cinched up well.

Bleeding dead simple and pedal feel and power much nicer than the old 15 year old Girlings. I have retained the original master cylinder after reading the threads on here and it seems A1 and a quality bit of kit..... Now for the track acid test. 

Wrightpayne
Wrightpayne's picture
Offline
Last seen: 16 min 55 sec ago
Joined: 17/04/2014

They look very similar to Canley Classics offering for the Herald / GT6.

 

timb2117
timb2117's picture
Offline
Last seen: 23 hours 12 min ago
Joined: 26/04/2020

I was advised that they were the same. Most impressive was the bolt on bolt off nature of them really an easy match up to the hubs and no difference in lining up (which is just as well because the steering rod end joint has barely 2mm clearance to disc!)

K7 VCT
K7 VCT's picture
Offline
Last seen: 2 hours 28 min ago
Joined: 17/04/2014
Glad to hear they are as described and working well

Orange is my new black

Ballistic orange 310s
John Vine
John Vine's picture
Offline
Last seen: 5 hours 17 min ago
Joined: 17/04/2014

...the copper sealing washer for caliper end...

Are you sure the washer is required?  I would have thought the convex end of the 1/8” BSP to M10x1.0 adaptor would self-seal in the caliper.

JV

 

 

Guy Lowe
Guy Lowe's picture
Online
Last seen: 1 min 53 sec ago
Joined: 17/04/2014

Not sure that using PTFE tape on brakes is good engineering practice. 

 

 

John Vine
John Vine's picture
Offline
Last seen: 5 hours 17 min ago
Joined: 17/04/2014

Re #6:

I agree.  But it won't be needed when the OP removes the washer and relies on the adaptor for a seal.

ETA: Re-reading post #1, I think the OP used PTFE simply to centre the washer rather than apply it to the thread of the adaptor.  But it won't be needed anyway.

JV

timb2117
timb2117's picture
Offline
Last seen: 23 hours 12 min ago
Joined: 26/04/2020

Yeah totally agree ptfe is ok for taps but that's it :)

Its only role was to get the pesky washer to line up centrally and stay that way as I tightened it up. I had already checked re the sealing with Jack as a an engineer this end queried the practice and validity, he works on v8 supercars and warned me that they get up to 700lbs of pressure - he cannot even press the brake pedal hard enough with both feet! 

 

John Vine
John Vine's picture
Offline
Last seen: 5 hours 17 min ago
Joined: 17/04/2014
The point is that you don't need the washer at all. It just happens to be in the hose pack that CC supply, just like the packs for the flex rear hoses.

JV

John Vine
John Vine's picture
Offline
Last seen: 5 hours 17 min ago
Joined: 17/04/2014

Re #9:

Apologies, I think I've got my fronts and rears mixed up.  Looking at my AP 4-pots, there is indeed a washer between the adaptor and caliper body.  I assume the Jack Webb calipers are the same.

But I'm still puzzled why the washer should be a slack fit over the adaptor.

JV 

 

aerobod
aerobod's picture
Online
Last seen: 2 min 35 sec ago
Joined: 17/04/2014

Usually there is an undercut of the thread to ensure the adapter mating surface is flat beyond where the thread ends, this means that the washer inner diameter is no smaller than the thread outer diameter, but the undercut diameter is less than the thread root diameter. This is why the washer can move around in the undercut, but normally it shouldn't move much off centre if it starts concentric to the adapter to begin with when tightening.

James