The 'E' Type Forum

Now that my e is nearly back on the road I find there is one fly in the ointment causing the MOT to fail. My garage (The Isle of Wight's Jag specialist) cannot get the handbrake to hold to sufficient power. The footbrakes are fine, and they have fitted new h/b pads and tried their best to bed them in on the rolling road and sneakily round the block but still it is down on one side. They said that new pads don't sit completely square when new (seems odd) which is why they need bedding in, and that the rust that was on the surface of the disc, now cleaned off, acted as a lubricant. The access is neigh-on impossible as you know. It is a shame that at this garage I can't get my overalls on and get under there, but are there any tips I could pass on to help the situation that might save them having to drop the entire IRS?

I am sure someone here had a fix for this although I can't recall who. It was either because the mechanism had been put together incorrectly or there was a modification of some kind. Try doing a search on 'handbrake'.

I think that could have been me. Never looked back since I did mine last year. 7000 miles on and itis just as good as my other cars. Try this link http://www.etypeuk.com/forum/viewtopic. ... =handbrake

Graham

Heuer wrote:I am sure someone here had a fix for this although I can't recall who. It was either because the mechanism had been put together incorrectly or there was a modification of some kind. Try doing a search on 'handbrake'.

David,

I have a permanent cure for the handbrake but I asked for it not to be put on any website. If anyone is interested I will send them details but it does require a bit of cutting and welding to original parts but not the linkage. I did mine 3 years ago after being told of this mod and have got to say it will never require adjusting again and will work as well as your modern daily driver. PM me for details.

Dave

Hi,

Handbrakes can be a problem and I think I understand the "not square" problem. The pads are on a mechanism which pivots to bring the pads on to the disc, which effectively means the pads swing through an arc. If your replacement pads are a little too thin when new, then as they pivot in, only a small area of the pad actually contacts the disc. My car came with a new set of pads which contacted nice and square, but when fitting them, one of the pads had the friction material fall off the backing pad. I ordered new, only to find the exact problem you described, i.e. the pads did not make square contact. I fitted them anyway, thinking they were all that was available and the when I came to adjust, I ran out of adjustment on the cable, the exact problem described by Graham (kgnich) in the link he posted above. These pads came from a show, so I don't remember their exact provenance, but I did later find that there are various types - maybe the ones the garage fitted were the wrong sort? (Incidentally, the garage say they fitted new ones - this is a fairly difficult job, only just possible with knowledge and some skill without dropping the irs. Adjutment of the articulated linkage is also difficult in situ, perhaps you could have another go? Also, did they fit the right ones - I believe that I may have fitted the wrong type when I originally ordered - there are a few types available to suit the many versions of Jaguar irs made over the years?)

My research led me to Grahams post and because I was both in a rush and in Australia, I did not have the time to order a new JEC cable so I modified the one I had, using the photos he posted as a guide, got loads of adjustment on the cable and passed my Roadworthy test the next day. Two weeks later, the handbrake failed and on looking, one of my new "new" pads had broken up and come away from the backing pad again. I ordered new pads again and fitted them. (I dropped the whole irs as I had other work to do at the same time). These pads did not need as much adjustment of the cable, but I cannot remember whether they met square or not. However, the fact that my pads still gripped the disc, but left more available adjustment at the lever, implies they needed less travel and thus met square on the disc. My New (latest) pads came from SNG, I ordered the cheaper set, although later wished I had ordered the "Greenstuff" pads they sell. However, the pads do work as they should and are reputedly made by Mintex - a reputable name, although they arrived in a plain white box, so may actually be cheaper alternatives. I hope this (and Grahams post) helps,

Regards,

Hi , I had a problem with my 3.8 fhc many years ago with the nearside brake being powerful and the offside feeble . Eventually found that both the spring forks needed replacing as a pair - I had one old one and one new one - the old (original) fork had much less spring in it than the repro new item. Changed this and all was well. It took me a long time and a lot of changed parts to see this.

regards tinworm

Thank you for your responses. With regard to whether they fitted the right ones, I ordered from SNG Barratts and took their guidance on the correct pads. I had them sent direct to the garage and Alec the Jag expert and boss at St Helen's Garage did not suggest that they were wrong, so I can only trust they were the right ones. I shall ask him to look at this thread to see if there is anything that can help him.

You can fit the 'correct' JEC cable, fit the right pads or for that matter the wrong ones, strip, plate, grease up the whole thing, spend ages setting it up and renew the forks (the forks only release the pads from the discs btw) and it will work for a short while and it then it will get steadily worse requiring more maints on the whole thing. The problem is it's a design fault. Standing at the back of the car looking towards the front when you pull the handbrake lever the right hand pad will start to pull up while the left one does nothing, once the right hand pad is up tight then the left one starts to move. If you spent enough time working on the system it will work OK for a while but eventually it will stop working.

What is required is a method to get both pads to pull up together and the answer to this is surprisingly simple and can be done by only removing the rear wheel, do the mod then refit it to get access to the mechanism to remove it. There is a company in the Midlands who charge ?250 to carry out this mod.

Regarding the bronze retraction forks - if they are not a matched pair the weakest will pull in first the strongest last - this will leave the lever angle beyond the optimum 90 degrees (for the best leverage) on that brake . Do you see what I am getting at ?

regards Tinworm

Dave K wrote:What is required is a method to get both pads to pull up together and the answer to this is surprisingly simple and can be done by only removing the rear wheel, do the mod then refit it to get access to the mechanism to remove it.

There is a company in the Midlands who charge ?250 to carry out this mod.

Who would that be, may I ask?

Andrew,

Sorry I can't remember the name of the company but I think they are based in Leicester.

Dave

The retraction forks don't have much impact on whether the handbrake works well or not, although if worn or distorted they can make adjustment harder. From fully off to fully on, the handbrake pads have to move closer together by an amount dictated by the pad-disc clearance. This movement translates, via the operating levers on each handbrake mechanism and then the compensating link, to a certain amount of "pull" in the handbrake cable. There is a limited amount of movement available in the compensating link due both to its construction and to the design of the outer/inner cable attachments to the link. If the pad-disc clearances are too wide, then there simply isn't enough movement available from the compensating link to bring all 4 pads hard up against their discs. The pad-disc clearances are set by the threaded adjustment rod which holds the rear ends of the handbrake pad carriers. If adjusted correctly, either by hand on the early cars, or by the self-adjustment ratchets in later cars, this ensures that the correct clearances are set and can be taken up by the available movement in the compensating link. All the retraction forks do is ensure that when "off", the pads are pushed away from the discs and that the available clearances are evenly shared between the four pads, to avoid any of the pads kissing the discs.

I suspect many handbrake problems are due to worn self-adjusting mechanisms which lead to excess pad-disc clearances. I certainly have this problem as on one side the self-adjuster will not deliver a close-enough clearance and I have had to "help" it by manually turning the rod a half-turn after removing the split pin which holds the rod head in position. Unfortunately, overhauling the adjusters requires removing the handbrake assemblies which is far from simple! It is probably possible to make up a slightly modified compensating link which has a slightly different leverage ratio, delivering more movement of the operating levers on the brakes for the same movement of the cable. I'm planning a go at this later in the year when I get nearer MOT time.

John : it's also noticeable how many of the adjusting pawls are in fact seized ( because of course it requires the pad carriers to be completely dismantled to service them ) and also how often the adjusters do not work because the split pins , which should go through the slot of the adjuster screw at the outer end , are missing , so that the screw turns, instead of remaining in a fixed position so that the pad carriers screw themselves on to the adjster screw

kingzetts

What you are saying is that it dosent matter if the forks are ok or not when it patently does. Assuming all the components are in good condition and properly serviced, lubricated and adjusted individually ,the only resistance to both levers moving together (which they must do in unison to give a good brake ) is the retraction forks, which are of course trying to open the pads . If the system is left so that one brake pulls up tight before the other one moves the last brake on WILL be poor as the brake lever angle will not be at its most efficient. If any E-type xj6 or any similar Jag handbrake is seen to pull one brake up before the other the reason must be investigated - usually it is corrosion that will cause it - but the brake will hang on partially on that side and tell you. If it is not corrosion then it must be the forks and both forks must be changed as a pair as stated by Jaguar . If you over- adjust to minimise the clearance on the first moving brake (in this situation - to encourage the other brake to move earlier ) this will cause the brake compensator (on E types ) to bend the mounting bar towards the cable which obviously needs to be avoided - jaguars pad clearance needs to be adhered to. The E-type handbrake will work well when properly looked after - it is vulnerable to neglect though and complicated with the compensator in the linkage.

It is not necessary for the two levers on the two wheels to move simultaneously. In fact it is almost certain that one lever will move before the other. Why? Imagine the mechanism on one wheel with the compensating link disconnected. When the tip of the operating lever is moved inwards, it will first of all move the pad carrier on which it sits outward until the pad on that carrier touches the disc. Further movement of the lever tip brings the outer pad into contact with the disc by pulling on its carrier via the adjustment rod. Thereafter the lever tip will not move any further, but applying more force to it to attempt to move it further will provide the clamping force needed to provide the braking effort. It is almost inevitable that the two levers and the mechanisms they are attached to will have slightly differing levels of resistance to movement. The whole point of a compensating link is to deliver an equal force to both mechanisms, which is why it is free to rotate about its mounting point. So when the cable is pulled and the compensating link delivers force equally to each side, one lever will move before the other. That doesn't matter - as soon as the pads on that side are clamping the disc, that side will present much more resistance to further movement than the other side and the compensating link will then increase the force on the other lever which will (unless it is totally siezed) start to move until it too is clamping its disc or until you run out of cable movement. The amount of initial movement of each operating lever required to bring its inner pad into contact with the disc is dictated by the total clearances on both pads, and the behaviour of the fork which is designed to share the available clearance equally between both pads. But (assuming the mechanism is fully retracted before the lever is operated) the total amount of movement is not affected by this starting point - if the inner pad is nearer the disc than the outer pad for a given amount of total clearance, the initial movement will be less but then more movement is needed to bring the second pad onto the disc, and vice versa. Unless there is massive pad/disc clearance, the angles in the linkages will never materially differ regardless of where the resting off position of each handbrake mechanism is.

I'm not saying the forks don't matter - they are there to ensure the pad carriers and operating levers move back to their maximum pad/disc clearances when the brake is released, and to centralise those clearances. If they are weak or distorted, it will be harder for the self-adjusters to work properly, and it will be harder to adjust the cable and compensator linkage accurately. They are important, but they do not materially contribute to the brake not locking both wheels. I entirely agree that Jaguar's pad clearances need to be adhered to. The specified clearances on the early (pre-self adjusting) e-type was 0.004" (4 thou) per pad, giving 8 thou total clearance per side. No value is given for checking whether the self-adjusters are working OK but I can say that on my car they were delivering much wider clearances than this, and this causes the handbrake mechanism to run out of travel before both discs are adequately clamped.

tinworm wrote:kingzetts

What you are saying is that it dosent matter if the forks are ok or not when it patently does. Assuming all the components are in good condition and properly serviced, lubricated and adjusted individually ,the only resistance to both levers moving together (which they must do in unison to give a good brake ) is the retraction forks, which are of course trying to open the pads . If the system is left so that one brake pulls up tight before the other one moves the last brake on WILL be poor as the brake lever angle will not be at its most efficient. If any E-type xj6 or any similar Jag handbrake is seen to pull one brake up before the other the reason must be investigated - usually it is corrosion that will cause it - but the brake will hang on partially on that side and tell you. If it is not corrosion then it must be the forks and both forks must be changed as a pair as stated by Jaguar . If you over- adjust to minimise the clearance on the first moving brake (in this situation - to encourage the other brake to move earlier ) this will cause the brake compensator (on E types ) to bend the mounting bar towards the cable which obviously needs to be avoided - jaguars pad clearance needs to be adhered to. The E-type handbrake will work well when properly looked after - it is vulnerable to neglect though and complicated with the compensator in the linkage.

Tinworm,

It really doesn't matter if the forks work OK or not their function is to remove the pads from the discs when the handbrake is released so they will not help with the linkages pulling up the pads only releasing them and even then they don't work very well. In order for the handbrake pads to stop rubbing on the disc, you can attach a spring to each of the outer clamshells, with the other end attached to the damper mounting bolts (or drill a hole in the cradle nearby) ? which assists the existing bronze retraction forks (which are totally inadequate anyway) ? these springs were eventually fitted on XJ6 models. The design of the handbrake lever is wrong once you accept this then you can start to move on and find a cure.

Dave

Many thanks for your comments chaps, but all compensating handbrake systems are the same in that when the handbrake gets to the position of starting to bite both operating levers need to be at the same angle or one will have a mechanical advantage over the other creating the brake imbalance that fails the mot . A weak bronze retraction fork on one side will achieve this with the e-type system (as will other faults as previously discussed) . Happy handbrake adjusting !

tinworm

Tinworm : All compensating systems are not the same . The compensator on the E is of a rather special type which depends on an action/reaction system to operate the 2 levers. One is operated directly by the handbrake inner cable, and the other is operated by reaction from that operation. Furthermore, there is an adjustable length link incorporated to provide further adjustment . Thus your remarks, although valid in relation to some compensators, are not in my view necessarily valid in relation to that of the E

That picture is useful but is missing a crucial part - the attachment block where the outer cable is attached to the other arm of the compensator. The compensator is like a pair of scissors, with each end of the blades attached to one of the handbrake operating levers, and with the inner cable attached to one handle and the outer cable to the other handle. Pulling on the handbrake pulls the "handle" ends of the compensator link together, which in turn pulls the "blade" ends together and pulls the operating levers on the two handbrake units towards each other. The mounting arm of the compensator link attaches to the link at the pivot point of the two arms and both arms (and therefore the whole link) are free to rotate about that attachment point. Because of that and as the outer cable is sufficiently flexible not to prevent the link rotating, the link equalises forces between the two levers. But the "blades" can only move towards each other by a certain distance until the range of movement in either the compensator kink or the cable is reached, and if this is not enough to fully clamp both discs due to poor adjustment and/or excess pad/disc clearances then the handbrake works poorly.