72 ser1 XJ6 brake booster

On my 72 XJ6 Can I remove just the brake booster? M/C is off. All the bolts can be gotten to and with the hood latch removed it will clear. I’m wondering if theres something attaching the pedal to the booster rod that can’t be gotten to if I do it my way. Seems my manual only mentions removing the entire pedal box as the way to remove it . I have a couple crushed lumbar vertebrae that really dont feel like going under that dash if I dont have to. Thanks for any advice on this matter-George

I have not been there. but, there is a rod from the pedal to the cylinder and booster in the engine bay.

Might search up a parts catalog with illustrations to check.

wow that was quick!. Does there happen to be a PDF of the parts catalogue for those on here anywhere? I have the service manual,but no parts book. and thank you

You’ll find the original parts catalogue pages here https://parts.jaguarlandroverclassic.com/older-vehicle-information (scroll down).

And, as everybody on this site is helping out for free and no one is selling anything to you, it might help you further to use a civil name and friendly address:-) We are a friendly bunch here and a classic car goes well with classic manners.

Good luck and stay safe


75 XJ6L 4.2 auto (UK spec)

thank you for the information. I dont quite understand why you would think I mean any disrespect. I have been here at Jag lovers for a long time,mostly finding and giving (when I can) assistance in the XK forum as I reconstructed my 54 XK120 from baskets and bins.Also finding help on my brothers 95 XJS. I apologize for any unintended unease I have caused you or anyone else. -George D Michener

Sorry George,

didn’t mean to raise a finger … Wonderful, if you’re a long time XK member, welcome to this forum! You’ll find a lot of accumulated knowledge and - most importantly - great people here!

Good luck with your brake booster! There was a thread on that not too long ago.


75 XJ6L 4.2 auto (UK spec)

No worries George, Jochen simply likes names (me too), it’s his usual message. :slightly_smiling_face:
I haven’t removed mine entirely but the pedal box is bolted in from below the dash.

The brake pedal link to the booster can be removed by removing the large rubber plug on the side of the pedal box, if that is not not there you’re out of luck, then it is get someone to unbolt the entire box for you I’m afraid. Four bolts from below and possibly the switch and not so easy to get back in, being upside down in the footwells was hell for me and I’m only 23. As far as I know it is a fork on the booster side that is connected to the pedal via a pin.


Thank you sir. the rubber plug you speak of…is it under hood or under dash? In my service manual it shows a clevis on the end of the rod,but it doesnt show anything else. I have a bad feeling I’m going to be breaking out the modified weight lifting bench I constructed for under dash work :roll_eyes:. I’ve been living with both this car and my busted back since the 80s so I have developed many “inanimate helpers”( the only ones that are always there when you need them). The physical therapist call it understanding your body mechanics LOL-George

This is the plug. Mine doesn’t have one I believe, they would have added it in the 70s…
Fascinating. The problem is probably bending over the sill and under the dash? It was for me. I hope you don’t have to. Good luck!

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thanks again!!! I’m driving over to the garage now to look a little harder for that! The real kick in the head is I’m only doing this so I can clean and paint that back corner of the inner fender and firewall. I will be rebuilding the master cylinder so I might as well. Thanks much-George

Well, the good news is mine had the plugs,I removed them pulled the cotter pin and the clevis pin-thus separating the pedal from the booster. The bad news is, there is not enough room to pull the booster because of the long studs sticking out of the booster er servo. The bottom of the servo hits the fender about 1/2" before clearing the studs.I could probably cut said studs shorter and get it out of there without anyone ever noticing a difference. That said, how much interior did you have to tear apart to remove your pedal box? Could you use extensions and reach the horizontal nuts? How many vertical bolts were the I see 2 nuts on the upper side of the vertical mount, but from the pic you sent me, there likely be bolts mounted in the casting at the bottom. In other words ,having done this job, would you be so kind to enlighten a decrepit old guy about the adventure. Thanks much, and sorry to be a pain.-George

Is there sufficient thread exposed that you can double nut the studs and wind them out?

there is. I’m not sure they’re threaded into the servo case though. Other non Jaguar boosters i’ve had apart just had flush head carriage bolts tacked into those locations. Do you know if they are indeed threaded in studs?-that would be great!

Hi George, I have taken the pedal box out of my 1985 S3, I’d bet it’s similar.

Removing the pedal box is definitely the way to go, but I can fully understand your reluctance to get under the dash, I’m 74 with a bad back and neck.

There are 6 nuts on studs under the dash that hold the pedal box on mine, along with the 2 under the bonnet, as you have mentioned. It sounds absurd, but after I managed one look under the dash to see the lay-out, I did everything by feel. You will need 3/8 drive ratchet, 12" extension, 1/2" and 9/16" sockets (mine has one!!! bolt that is bigger than the others), a trouble light and a largish mirror. There isn’t much in the way as far as wiring and the process is pretty straight forward. Tip: remove the rubber pad from the foot pad. The foot pad just barely comes through the hole in the fire wall without the pad, not at all with the rubber pad in place. I also had the seats out when I remove this, which made a world of difference.

Going back in is just the reverse. You will be surprised how much you can do with just your hands and visualizing in you mind.


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I agree with the above lister who advised remove booster from beneath

careful planning is the key if you have back issues, the mirror and strong light allow you to do this job without too much back bending or twisting…if you are careful and patient

alternatively a youngster can reach in and wrench the 6 nuts out in a few minutes

You are also correct its the perfect time to correct any corrosion or poor paint in behind,
brake fluid (and fumes) are nasty for that

It does, George - but actually, the pedal rod is connected to the booster with a clevis pin, which should be accessible from the engine compartment, as Carl says…

xj6 85 Sov Europe (UK/NZ)

Thanks for that information Dave. Not absurd at all…I do my best work in the dark, at arms reach, and out of sight-lol. When I was younger all of that meant something completely different -sigh . Might be a good time to replace some carpet and some other interior,thus removing the seat. If it wasnt for that dreadful shelf under the steering wheel things may be a bit easier.- George

Frank, yes, I got to the pin and removed it,but the length of the 4 bolts/studs which attach the servo to the pedal box wont let it clear the contour of the inner fender on the bottom…even with the bonnet latch removed up top, the bottom of the servo just wont quite clear without shortening those bolts. A cautionary tale for others maybe? -George

Not ‘maybe’, George…

Obviously, someone knew when writing the manual - and changed the set-up on later models…?

xj6 85 Sov Europe (UK/NZ)

Aye, those were the days… Nothing but fond memories…