deep Posted October 19, 2015 Share Posted October 19, 2015 Last week I finally got my ex-Singapor military 110 through the nasty VIN process and it's road legal. 20 miles later, I seem to have had a vacuum failure in the braking system. Groan! I am after some advice, please. The brakes had been absolutely fine. While I was playing on a friends farm (going up and down steep, rutted hills at the time - it is, after all, a Land Rover!) the brakes suddenly went very firm and ineffective. Suddenly, as in, they worked, then the next time I used them, they didn't. The pedal was so firm that the brake light didn't go out unless I jiggles the pedal. However, the brakes weren't binding and still worked with a very hard press. I brought the car home and investigated. It seems, when you first touch the brakes, there is a definite hiss from the booster and there is a fraction of help from it for the first millimetre or so of pedal travel. Any firm push, though, and that assistance is gone. My various manuals haven't been much help. An internet search suggested the push rod from booster to master cylinder may have been set too long. I have now wound that in (I got around 3/16 of an inch or so). That has actually helped pedal feel a lot and sorted the brake light issue but there is still virtually no vacuum assistance. There is enough braking power to lock the wheels but that is all coming from my right leg. When I first put the car together, there clearly was no vacuum boost. That problem was quickly traced to a worn out belt-driven pump (it has the 18J motor, largely the same as the 12J naturally aspirated diesel but not identical). Much to my amazement, it turned out to be cheaper to buy a whole 19J motor and take the pump out of that than to repair the old pump. When I did that, the brakes were simply fabulous. I can confirm that the pump is still happily sucking away like it did when I fixed it, so can't believe that is the problem. In my investigations, I see that a spider-killing wasp has made a nest in the top of the pedal box - it is quite likely something has crunched up while I have been driving. I took the master cylinder off and worked the pedal several times though its full travel and it certainly feels like something has "un-crunched". Still, the brakes aren't boosting. I've done the "start the motor while your foot is on the brake" test and the pedal remains firm. The other test of running the motor for a while, then pump the brake and listen to the hiss yields one decent hiss but no second one. I have also tested the valve on the booster outlet - you can definitely suck but not blow past it. I can't detect any leaks while idling but it is a rattly diesel.. So, my question to the learned amongst us is: Is this something that could be fixed by fitting a repair kit or is a new booster necessary? For those wealthy people who would just fit a new booster as a matter of course, you should know this rebuild has put me a fair way in debt and anything I buy now is coming off a burdened credit card. I don't want to pay for anything I don't need! Thanks in advance, Don Quote Link to comment Share on other sites More sharing options...
deep Posted October 19, 2015 Author Share Posted October 19, 2015 P.S., for what it's worth, I think this is the type 50 booster. Quote Link to comment Share on other sites More sharing options...
deep Posted October 20, 2015 Author Share Posted October 20, 2015 Never mind. I pulled it off the car today and had a better look. It rattled when I shook it. When I pulled the check valve off, a big hunk of broken plastic fell out. That explains what the problem was but I may be scratching my poor head for a few years trying to work out how something actually can break in there! Quote Link to comment Share on other sites More sharing options...
GW8IZR Posted October 20, 2015 Share Posted October 20, 2015 sometimes plastic stuff just deteriorates with age and exposure to hydrocarbons / UV / heat whatever. Its usually a badly chosen plastic in the first place but twenty od years later ( or whenever ) we get to find out. Anyway you are on the case so good luck with the fix. Quote Link to comment Share on other sites More sharing options...
deep Posted October 20, 2015 Author Share Posted October 20, 2015 Ta. Oddly, the plastic still looks very new and shiny. However, it did sit in Dubai for a while in intense heat so you might have a good point! Today's initial search for a replacement wasn't promising though. Apparently there is a big demand for second hand ones and a few suppliers here don't have new ones. Hmm. Better luck tomorrow? Quote Link to comment Share on other sites More sharing options...
qwakers Posted October 20, 2015 Share Posted October 20, 2015 how about going electric? looking at that myself for my challenge motor as my mech pump is worn out..... Quote Link to comment Share on other sites More sharing options...
deep Posted October 20, 2015 Author Share Posted October 20, 2015 how about going electric? looking at that myself for my challenge motor as my mech pump is worn out..... Let's not go there! I had to buy a whole motor to get a decent "standard" pump as the original was a Santana-type belt-driven one I couldn't find diaphragms for. Having spent a lot of time welding up the old one, making diaphragms myself, which lasted five minutes (and boy, do they spray oil when they let go!), and then trolling the internet for ages looking for the best solution, I'm quite happy to leave things as they are now. The pump is fine, it's the booster itself which is broken. (I'm awaiting a call from a friend tonight who may have a spare.) Quote Link to comment Share on other sites More sharing options...
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