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General Brake Info - Europa, Elan & Seven
The following was posted on the Europa List by Tim Engel on March 9, 2005 Gentlemen, Here's some miscellaneous ramblings... Brake pads will carry different part numbers for different compounds even if they are dimensionally interchangeable. All else being equal (?) a harder pad will be more appropriate for a heavier car and a softer pad will be more right for a lighter car. So don't use pad listings as an indicator of whether or not the major brake system components are interchangeable between cars. The Herald/ Spitfire/ Europa and Vitesse/ GT6/ Elan brake pads are dimensionally the same. LOTUS front pads are the same for both the Europa (Herald/ Spitfire) and Elan (Vitesse/ GT6).
The Spitfire is based upon Herald parts and the GT6 was based upon Vitesse parts... not the other way around. Sedans came first, then the sports cars spun off from them. Under the skin, the Vitesse and Herald parts are very similar in concept and layout, with some bits like ball joints, trunions and tie rod ends being shared. The Vitesse was heavier than the Herald, so things like brakes, uprights, spindles and bearings were heftier. The big difference in the brakes is just the disc diameters. The calipers were similar but mounted further out on larger mounting brackets. Since the bracket mounting hole patterns vary on the different uprights, the entire upright assembly must be swapped if you wish to install the larger brakes (ie, discs) into a Europa. The mid-engine Europa (light front) got the lighter Herald/ Spitfire parts... along with the smaller brake discs. The front engined Elan (heavy front) got the Vitesse/ GT6 bits... along with the larger disc brakes. The more powerful Elan/ Vitesse/ GT6 front brake discs can be fitted to a Europa, but it's a complete package deal. Everything between the ball joints and trunions must be swapped... vertical links, spindles, bearings, steering arms, etc. are also fitted during the swap. Before you jump on that idea, read more comments on Europa brake response near the end of this message. Europa Brakes
FRONT CALIPER APPLICATIONS
Europa S2, thru 9/71
Super 7 S4, ? thru 9/71
Elan Sprint, 9/71 on
Pre 9/71 and post 9/71 calipers differ only in the thread used for the brake line fitting. They can be interchanged if the appropriate thread adapter fitting is used. Elan S1, S2, S3 thru 9/71
Elan S1 thru - (date ??)
Elan +2, after 5/72, after Chassis 0275N
Elan +2 1969 thru 4/72, From Chassis 1857 on
Elan +2 1968 - 1969, thru chassis 1856
EUROPA REAR DRUM BRAKES
Wheel Cylinder Rebuild Kit, Europa S2
Europa rear drum brakes can be upgraded to twin-leading shoe type with two wheel cylinders per brake. They are approx. 40% more powerful, and give the car more balanced braking (however, see comments below on response time). The back plates are of Girling manufacture and were standard on the FRONT of early Sunbeam Imp's. Similar ones are on the front of early Triumph Herald's. Recess the center of the plate approximately 0.125" so the shoes are closer to the center of the car. This is necessary so as to fit the 1.50" shoes and still maintain the desired rear track (first Twin Cams used 1.25" shoes, S1, S2 & Spcls have 1.50" shoes. Still necessary??). BRAKE RESPONSE:
The Europa brake issues stem from having discs on a very light-weight front end paired with rear drums. Disc and drum brakes respond at different rates, with the front discs biting "right now" and the rear drums taking a finite time to self-energize. Under rapid application (ie, ya stomp on 'em) the lightly loaded fronts come on first. In that brief split second before the heavily loaded rears pick up their share of the work... and before chassis weight transfers to the front tires... it's extremely easy to lock up the front tires. Once locked you must basically release the pedal to unlock them. Since whatever was motivating you to brake so hard is not much closer, the natural inclination is to stomp on the pedal even harder... and you slide right into the middle of a problem. Upgrading the Europa's rear brakes to discs doesn't have to mean installing massive, ventilated discs. Small, light weight disc brakes sized to be balanced with the stock fronts would be fine. The main advantage won't be more braking "power" as much as matched response times. Matched response times would make it "easier" to apply the brakes rapidly with less risk of locking up the fronts pre-maturely... and therefore easier to use the full braking potential. Installing Vitesse/ GT6/ Elan front brakes to improve the Europa's braking isn't the answer either. More power isn't needed, but the larger brakes may be easier to modulate. However, I've seen a number of autocross Europas with upgraded front brakes still lock up the fronts frequently... at all the wrong times. The more powerful brakes weren't the answer. Balanced response times would help more than larger front brakes. Once you get the brakes applied without initial lock-up, then easier modulation would be an advantage. Of course, the real answer is proper technique. Optimal braking is never achieved by mashing on the pedal, even with a balanced system. Discipline and self-control are required for threshold braking in any car, and it's even more critical in the Europa. Apply some initial pressure to start the braking without locking up the fronts. Then as the chassis reacts and weight transfers forward onto the front tires, bring in more pedal pressure. More pedal = more weight transfer = more pedal = etc. The trick is to smooth, progressive and quick without stomping on the pedal so fast the fronts lock up. Target shooters know the difference between jerking the trigger and pulling the trigger smoothly but "quickly". Same thing with braking. It takes practice to develop the touch and discipline not to forget it when the red mist sets in. The Europa's brakes are not short on power... they are appropriate to the weight of the car for street and autocross. It's just that the extremely light front end weight combined with a disc/ drum brake system makes it very challenging for the driver to achieve maximum brake performance. Train the driver before you spend tons "fixing" the brakes.
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