Jag handbrake set-up...

Plums · #1 (**permalink**) 09-17-2007, 07:21 AM

For those of you with Jag rear brakes, how do you get the handbrake to hold anything at all???

I have adjusted it as well as I can, (well at least I think I have) and it's as weak as p!ss!!! It won't even hold the car when I put it in gear...

Any suggestions are welcome!!!

stephen low · #2 (**permalink**) 09-17-2007, 07:40 AM

Bobby sounds like something's missing.

Wouldn't say my h/brake's great but you can't push the car with it on. Not sure what it will be like on a slope though.

Have to admit the brake lever has a long pull to get the brakes on and I am yet to really adjust mine.

Sorry no great suggestions!

*Cobber* · #3 (**permalink**) 09-17-2007, 07:31 PM

Bobby,

The Jag park brakes are s^&*, if you have new pads in they may take a bit of time to bed to the right shape. Just keep adjusting them up as much as possible, they should come good.
Check for oil on the discs as well if they are new.
The auto adjusters on the brakes sometimes get all gummed up as well, it is worth making sure they all work correctly.

Handbrake turns were never a strong point for Jags.

Cheers

Rebel1 · #4 (**permalink**) 09-17-2007, 07:58 PM

I agree, check the self adjusters operate well.

When installing new hand brake pads you need to "grind" the pads so they make full contact with the rotor. Install the pads "unground" and use the rotor as a guide to mark the pads with a marker. Then grind off.

When the car is up and running use the hand brake lever to bed the pads properly.

CHANMADD · #5 (**permalink**) 09-17-2007, 09:07 PM

Adjusted properly I can almost lock the rear wheels doing 25mph.

Ross Smith · #6 (**permalink**) 09-18-2007, 03:14 AM

Hi Plums,

I have a Jag handbrake in my RMC and it will only hold the car when it is on a level surface, certainly not any good for hills. I have been told that is pretty standard, but I do wish it was better.

Ross

Naumoff · #7 (**permalink**) 09-18-2007, 03:49 AM

Do you have inboard disc?

If yes do you have pull off springs on the park brake calipers?
The springs that are on the calipers are not strong enough and will let the pads stay contacted to the disc and wear down.So you have to keep adjusting them.

I have a limited pull on my replica jag brake handle so I made a longer lever that attach's to the handle. Giving it a longer throw.

Plums · #8 (**permalink**) 09-18-2007, 05:24 AM

Quote:

Originally Posted by Ross Smith

Hi Plums,

I have a Jag handbrake in my RMC and it will only hold the car when it is on a level surface, certainly not any good for hills. I have been told that is pretty standard, but I do wish it was better.

Ross

That seems a bit unsat. How did you get it through rego??? More to the point, how will I get mine through?

I know in Darwin they put your car onto the brake test machine (like a reverse Dyno where your brakes have to retard the rollers).... Geez I hope they don't do it here....

Rebel1 · #9 (**permalink**) 09-18-2007, 06:09 AM

Plums, check how much of the pads are actually clamping the rotor.

I noticed with mine that a very small area of the pad was marked after use.

Keep in mind how the thing works..... The pinchers pivot on the bolts thru the caliper lugs which are a fixed distance apart. The levers which cause the pinchers to close are at the other end of the pinchers. If the pad is new and a bit thick, only a small part of the pad ( that closest to the pivots) will contact the rotor, but will then prevent the rest of the pad to clamp the rotor.

Sometimes...depending on the make of pads, you may have to taper the pads a little on a grinder. You will need to grind that part of the pad closest to the pivots so that when the levers compress the pinchers ALL of the pad clamps on the rotor.

The hand brake pads are small enuff as it is so you need all of the pad area to contact the rotor to have an effective hand brake.

Mate, they worked on the jag (in a manner) so should easily work on the cobra.

It's all in the initial fitting and adjusting. Once right, the auto adjuster will look after them.

*Cobber* · #10 (**permalink**) 09-20-2007, 07:28 AM

Bobby,
A few steady laps round the block pulling the hand brake on and off should bed them in.... Dont let them get too hot.

You will also find that the spinginess (if that's a word) of the hand brake will also get less as the pads take shape and the adjusters take up the slack.

My brother in th UK has owned a V12 xjs for the last 20+ years and I remember him having the same problem.

The good news is they will come good, not great but good enough.

CHANMADD · #11 (**permalink**) 09-20-2007, 08:51 AM

I did the rego thing in South Africa with the same brake test machine and passed,they work OK but you are not going to do handbrake spins with the car.

Plums · #12 (**permalink**) 09-20-2007, 06:15 PM

I've been doing something similar Andy, (forwards and backwards in the driveway, not round the block, don't have brakes yet) and it seems to be slowly (very slowly) getting better.

You may be right about the "springiness" too. I reckon the handbrake cable will be stretching a bit when it's new...

stephen low · #13 (**permalink**) 09-20-2007, 06:59 PM

Bobby

The way I've set mine up, I have the standard Jag aduster at the passenger hb lever at the caliper but also used a small s/stell turnbuckle in the cockpit between cable and h/brake lever.

In this way I can relatively easily wind on more tension to the cable if required to achieve more h/brake purchase. Well that's the theory anyway!

I reckon I'll do a bit of handbrake powered stopping once mobile to bed in the new pads in my brakes too!!

CHANMADD · #14 (**permalink**) 09-20-2007, 07:34 PM

First the disc has to centralized in the caliper with the shims on the output shafts.The handbrake caliper should put the pads pretty evenly against the disc.The little U shape springs that go the handbrake calipers should be bent back to nice and straight so that when they are mounted they hold the pads just off but close the disc.The screw in the calipers that hold both together withe the splitpin should be adjusted to the same just off the disc.Then put the split pin back. Adjust the cable and then just hold the handbrake button in and pump the handle up and down a few, maybe more ,times and it should be right

Ross Smith · #15 (**permalink**) 09-21-2007, 05:07 AM

Hi Plums,

I adjusted my handbrake pads with feeler gagues to the clearances specified in the Jag manual. I think the poor grip is due to the amount of cable travel required to pull the calipers together and I am sure that the handbrake we are using is nothing like that in the original Jag. My car has the paperwork in at the DPI Technical Section in Welshpool waiting for the "invite" to come in and put it over the pits. I have been told that will take from 10-12 weeks before that happens! I will let how I go with the hadbrake, I believe that the only "give it a push" when parked on the level and my handbrake holds fine on the flat.

Cheers

Ross

Plums · #16 (**permalink**) 09-21-2007, 08:51 AM

I got my VIN yesterday and the guy from the Technical Section said it normally only takes about 2 weeks from the time they receive your engineering paperwork, till they send you the letter!!!

Ross Smith · #17 (**permalink**) 09-21-2007, 09:18 AM

Hi Plums,

I hope that you are right, my paperwork has been in for 2 weeks and the only news that I have is that I had to go back this week and pay $50 for a Vehicle Standards Exemption Fee to cover the sidepipes.
I will be sure to let you know how long it takes.

Ross

Rob. Smith · #18 (**permalink**) 09-22-2007, 05:52 AM

I did away with the cable and made a linkage to operate the pads. I was required to do a 30 degree incline park brake test. I did this on the back of a tilt tray truck. It worked well. I felt the cable had too much slack & "stretch" It felt soft. So I made a bell crank lever to operate the pads.
Smithy

Harrymac · #19 (**permalink**) 09-22-2007, 08:32 PM

Hello Rob,

Do you have a diagram of your handbrake set up, or even a photo it sounds great. Particularly on the 30 degree tilt, thanks.

Harry.

Naumoff · #20 (**permalink**) 09-23-2007, 03:12 AM

Quote:

Originally Posted by Rob. Smith

I did away with the cable and made a linkage to operate the pads. I was required to do a 30 degree incline park brake test. I did this on the back of a tilt tray truck. It worked well. I felt the cable had too much slack & "stretch" It felt soft. So I made a bell crank lever to operate the pads.
Smithy

That sounds like a great ideal.
Do you have any photos of your bellcrank?