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adjusting separate parking brake provision, how?


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Hi all,

Just finished installing bigger brakes on my Esprit. So, I have some rear calipers resembeling the HiSpec rear calipers with the seperate handbrake provision - cables pulling it's own two small pads.

I have slackened the cables fully in the front, next to the seat, to make the handbrake cables long enough to reach the mounting bracket at the rear. Only just, but doable. I have installed the handbrake cables in the holders provided on the rear brake calipers.

I have also tightened the bolt to make pads as close as possible to the new brake discs, without braking the rear disc in rotation, when parking brake is not pulled. You know, a tiny bit of being slackened, so they can juuuuust rotate freely, without any drag from the parking brake pads.. Then tightened then bolt and securing nut. Cannot feel any slack or movement in outer sheath on hand brake cables, when pulled or not. They seem pretty tight in place.

I have not then tightened the cables in front next to the drivers seat.

What I have now is excellent working brakes, and no parking brake effect. I cannot pull the hand brake handle (lever) as I used to (all the way up, but effective), but only 2, max. 3 clicks. Then it's really hard. But I can spin the rear Wheels, and/or very easy push the Esprit. I've read what I could on this and other forums, but not found any real advice on the matter.

Any Ideas, so i can get it working? (really need to).

Should I tighten the two cables connections in the cabin?

What am I missing?

I know this brake is notoriously known for not being a pull-and-spin-around-with-screaming-tires-brake, but it needs to be at least able to stop the car from rolling Down a (slight) hill when parked.

Any advice is very greatly appreciated, and to the one who can give me the decisive advice that solves my problem, I'll happily mail a small Esprit as thanks ;)

Kind regards,

Jacques.

Nobody does it better - than Lotus ;)

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Pete at PNM Eng was telling me the other week that he is very close to offering a separate electronic parking brake. I'm definitely going to purchase one as I've toiled for hours trying to get the cur

Thanks Steve, but these calipers Work in a different way. The cables are going into a common arm that eases the force you have to use pulling the parking brake. Tehn it splits into two cabel holders,

I spoke to PNM last week about the parking brake caliper, and am waiting for some more information. I believe the intention is to have either a single piston rear caliper incorporating an electronic p

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Hi Jacques, try slackening off the cable adjusters to allow the actuators /levers on the calipers to move back as far as possible, there may be a marking on the caliper to assist with alignment, then take up the slack on the cables, pull the hand brake on and off a few times to enable the self adjusters to set themselves. Then re adjust the cables as necessary.

I'm just guessing from experience working on other makes, but it may be worth a try.

Steve

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Thanks Steve, but these calipers Work in a different way. The cables are going into a common arm that eases the force you have to use pulling the parking brake. Tehn it splits into two cabel holders, each having a cable adjuster to it. Then the two cables directs to the calipers, and they have no self adjusting mechanism as per ordinary rear calipers. It's an entirely separate mechanism, not interacting with the 4 pistons in each rear caliper. Instead the cable pulls an angular arm on which a small separate brake pad is attatched, plus the arm protrudes via a bolt and locknut to the other side of the caliper, which also have a similar arm and a small pad attatched to it.

To adjust this, you can adjust the cables at the handbrake lever manually, and likewise on each brake caliper.

Anway, still needs good advice, so I can make it Work propperly.

In Lotus Service Notes it is described, that there should be a specific distance from the cable reaching the cable holding arm, to the end point of the cable - if i remember some 60mm. This is go give the right reaction momentum, I suppose. This is not really the same on these rear calipers, although there may still be some truth in it, idea-wise.

Kind regards,

Jacques.

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Nobody does it better - than Lotus ;)

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Photos may help a bit Jacques.

All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

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Hi Jacques

 

 

Sounds to me as if the cables are not initially providing enough movement to press the parking brake pads against the rotors?

If you agree, then you need to adjust them of course.  Not sure if you can apply any dimensions from the Lotus manual since they are aftermarket.

 

I'd pull the handbrake up one click, then adjust the common cable by the drivers seat, until you get drag. You may THINK you have it adjusted this way but the new cables have slackened since you put them in. Once one side starts to drag, adjust the other side for equal force. The brakes should not drag significantly when the handle is released totally.

 

The one thing I'm key on, is your statement that you were just barely able to get the cables to 'reach' when you installed the brakes...

 

Perhaps you also need to verify that the pads move in when the cable is pulled?  I guess they could be 'stuck' from sitting on a shelf.

I agree, pics of the setup would help.

Atwell Haines

'88 Esprit

Succasunna, NJ USA

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Thanks all,

I've been real busy with other Things today, but I'll take a few snaps tomorrow.

So, I know for sure that the pads (1 small pad per side on each rear caliper are moveing, as I've played with them before installing them. So I know the pads move freely.

Since these calipers are different than the Toyota Bendix arrangement (or whatever), I had to shorten the length from handle to cable rear attatchment, by loosening the cable adjuster nuts in the left side footwell, near the hand brake lever, and turn the thread inwards, so in effect I shorten the outer sheath, thereby obtaining more length on the inner wires themselves.

3 clicks is all I can pull the hand brake lever now.

I adjusted the bolt on each rear caliper related to the "attack" of the parking brake pads, so, that they are very close to the brake discs. I mean close. In effect that means to turn in in, moves the reaction arm so that the pads come closer to the disc, and then back off a tiny bit, torate the disc and see if there's any noticable drag.

The parking brake cables are not new, so they may have stretched all they will at this moment. But new ones are on the shopping list. Always good to have something like that on the shelf at home.

I agree, that there may be some extra slack in not having adjusted the two parking brake cables at the other end, the lever end in the cabin. So, I'll do that tomorrow after having hopefully confirmed, that the main brakes are working satisfactory, bed them in and brake quite hard to see what they can do. I think I'll have to do it in this way (not the bed in procedure, but the logical sequence), so I don't need to take it all apart again with regards to the parking brake, if something else shows up. Hope not, it seems fairly solid. i have run 3 Liters of fresh braks fluid through the brake system, and I have installed fresh braided brake hoses as well, to supplement the new calipers, pads and discs.

I'll report back tomorrow.

Kind regards,

Jacques.

Does this Picture help?

 

park.JPG

Nobody does it better - than Lotus ;)

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Based on that photo, I think you need an anchor for the outer cable on the chassis so that the inner pulls on the lever that we can see?

How are you anchoring the cables where they meet the caliper?

All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

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On the back side of each rear brake caliper is an attatchment into which you press the complete cable. That is the anchor, and holds the outer sheath steady. Well seated, and then you move the spring loaded lever arm (on the Picture, it is the inner most arm) towards cable end, and can press in the cable end into the holder, that holds the Little "ball" on the cable end. Very simple and easy to Work with.

Then you tighten the bolt on the end of the brake caliper so, that the special parking brake pads (also in the rear end of the caliper), com as close as possible to the brake disc.

On the Picture, I had not yet attatched the cable to the caliper.

Does that give any meaning?

Kind regards,

Jacques.

Nobody does it better - than Lotus ;)

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Well as far as I can tell, if you have done all that, I would get someone to watch the operation when you pull on the hand brake or do some measurements to make sure that things are moving.

It is all relatively simple. If it isn't working, then something isn't moving or isn't moving enough.

All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

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Something broke in the parking brake lever, when I pulled to experiment today. Didn't have time to pull the seat and investigate. Oh well, I'll look at it asap. It seems it's very difficult to make a parking brake... Other than that i tried to bed in the new pads, and it seems to slowly come alive, so that the car can actually brake when need be. Preferably a lot better than the tyota/what ever setup. We'll see.

Kind regards,

Jacques.

Nobody does it better - than Lotus ;)

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Okay, it was the parking brake cables taht left the rear calipers.  Modified to fit propperly, they won't move away from the calipers.

Adjusted everything as tight as possible, but the parking brake is mildly spoken appaling.

Any ideas from those WHO have 4 piston hispec rear calipers with the built in parking brake function?

I mean, how do you actually get it to perform?

In my view, it's one of the most bad designs ever, as it does not transfer any power to the pads, so they can grip the discs.

Also, has anyone tried to install a seperate parking brake caliper in the same time as using a hispec 4 piston rear caliper? Brackets?

Kind regards,

Jacques.

Nobody does it better - than Lotus ;)

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Which it is surely not. Don't really understand why it was made in the first place. Maybe for some other cars, whita totally different system.

But the Electric parking brake system/caliper have been underway for years. Maybe soon? Meanwhile, it would be awfully nice to know what others have done to sort it out, sort of.

Kind regards,

jacques.

Nobody does it better - than Lotus ;)

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I spoke to PNM last week about the parking brake caliper, and am waiting for some more information. I believe the intention is to have either a single piston rear caliper incorporating an electronic parking brake, or an electronic spot-caliper which is mounted on a separate bracket to their 4-piston rear caliper conversion.

I'm waiting for a reply to an e-mail, which I should chase up, but if I do hear of anything more I will post it up.

Meanwhile - http://www.hispecmotorsport.co.uk/electronic.html

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Margate Exotics.

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Thanks a lot Ian, I'll be very interested in hearing everything and anything about it.

Dis anyone actually get the hispec 4 piston plus parking brake Facility to Work ever?

Kind regards,

Jacques.

Nobody does it better - than Lotus ;)

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Had to use electronic parking brakes on cars where I worked recently. Ok on an auto. An unmitigated disaster on a manual if you are pointing up a hill.

All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

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Just a thought:

Is there a mis-relation between the movement of the parkinf brake handle/cable pull and the reaction arm on the rear brake calipers on this type, so that the parking brake handle movement does not get enough pull (kilo) on to the pads?

Kind regards,

Jacques.

Nobody does it better - than Lotus ;)

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Another thought:

Does anyone know, if you can actually adjust each pad individually? So that when you adjust the lever arm which moves both pads, there is no longer one pad that brakes and one that sits there not doing too much?

What I mean is this: as the cables pull the parking brake pads the parking brake steps into action and hinters the wheel from rotating.

Now, the adjustment of both the level of how hard it pulls and individually from left side and rear side Wheel, is made solely on the two adjusters next to the drivers seat. I suppose that is correct?

If that is so, it must mean that the two little parking brake pads on each rear brake caliper is not affected by the bolt between them, That bolt must be the adjustment of the relation between the two pads (on each caliper).?

If that is so, misadjusting that bolt must mean that for example only one pad on one caliper brakes a wheel, were as if that bolt connecting those two little pads is adjusted correctly, they will both be in action, with the same amount of pressure. Is that correct?

If so, I need to go and measure up exactly how much force each little pad excerts on the disc, and when propperly adjusted, I "may" have a working parking brake.

It would be nice to know if someone else have done this with a propper result. ;)

Willy nilly, I'll report back with what I find.

Kind regards,

Jacques.

Nobody does it better - than Lotus ;)

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There is a compensator lever between the handbrake lever and the cables going to each wheel. This ensures equal force is applied to each wheel. Provided both cables are properly adjusted. Because of its design (more like a triangle than a straight lever), the compensator plate will only work when it's close to vertical. So if one cable is much shorter, the other one will get less pull. You mentioned you had difficulties getting the cables attached and that they were only just long enough. This could mean there is a difference in length between the adjusters and compensator, which results in a difference in force when the handbrake is applied. Check the brake section in the manual, it's a lot easier to understand than my ramblings. ;)

I have made many mistakes in my life. Buying a multiple Lotus is not one of them.

 

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Thanks Filip, will do.

I took it apart today, and looked at the compensator. It looks to be propperly situated and cables adjusted. I then loosened both cables fuly on the adjusters NeXT to the drivers seat, and then went on to take out the brake pads (ordinary ones, not the small parking brake pads), to get a free view to the parking brake pads. This way it's much easier. I took the connecting bolt between the two parking brake pads off and inserted a return spring (quite hard spring tension) on both calipers. Then I shortened the two longer connecting unbrako bolts by apprx. 5mm, and then reinserted those two bolts, washers and nuts. This time adjusting that unbrako bolt while having a close look at how close the two pads came to the brake disc. As they were near, tighten everything up, and test the parking brake. MUCH better. No rotation of Wheel at all. Do it a few more times to gain the last bit of slack into pad grip instead, and then adjusted the parking brake cables at the adjuster level NeXT to drivers seat. Seems quite okay now. Inserted the brake pads (ordinary ones) back into calipers as well as pad pins, clips etc. Will have to test drive and test park Tuesday or wednesday though, as it got real late.

I think this is the propper way to adjust it all.

I am keen on making the solution Mitch did with the Brembo calipers in tandem with the other primary calipers. Something for the Summer after Nurburgring, Sturup Raceway and Knutstorp Raceway which is the following 2 weeks.

I'll report back on braking and parking performance asap.

Kind regards,

Jacques.

Nobody does it better - than Lotus ;)

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If you're luck is the same as mine, you'll  probably just get this all working perfectly by the time the PNM electronic spot calipers become available. 

Margate Exotics.

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Well, I think not, unles that a fair way into the future, as my rear left side caliper just broke Down and I need to source another caliper or get it laser welded.

Meanwhile, I now have a working parking brake as I did what I suggested in the above ....  ;)

Such is fate.

That also Means I won't be going to Nurburgring on this Friday (after 1½ years and 5000 gbp's of preparation)... ;(

Kind regards,

Jacques.

Nobody does it better - than Lotus ;)

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Okay, caliper repaired and parking brake working okay as well. Done 560 Km with new discs and pads etc, so brakes are getting fairly better than before. Medium pressure makes my fire extinguisher fly out of it's holder. So it must be braking somehow ;)

Kind regards,

Jacques.

Nobody does it better - than Lotus ;)

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  • 4 weeks later...

I have Hispec 6 pots on the front and 4 pots on the rear, they are from PNM all acting on larger rotors, never ever had the parking brake working, all the angles are wrong and despite hours of faffing about I gave up. I would be interested to hear of anyone who has made them work. I am concerned that I bought these with a hand brake, for MOT reasons and its never worked, the fix should be either from PNM or they should supply an electronic version FOC.

 

Dave

 

 

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