Riceburner Posted January 25, 2020 Share Posted January 25, 2020 Hey guys, My brother has recently rebuild his 1600, All stock brakes. New JB1181 master, 3/4'' non boosted, residual pressure removed from front nearest to fire wall, front calipers fully rebuilt with all new parts, new rear wheel cylinders, new pads, shoes and hoses. He still has issues with the front calipers holding pressure after repeat stops in short amount of time. Is there something we are missing? Quote Link to comment Share on other sites More sharing options...
1600dave Posted January 25, 2020 Share Posted January 25, 2020 (edited) JB1181 is a 180B master cylinder. Aussie delivered 1600's only had a single circuit, unboosted brake master cylinder. What other mods has he (or a previous owner) done to make the dual circuit master fit and function properly ? You shouldn't have needed to remove anything from the master cylinder, its designed for a front disc / rear drum setup in a 180B so should work fine as-is on the front disc / rear drum setup in a 1600, assuming all plumbing is correct (see first point above). Is the symptom that the front calipers are defintelyholding pressure, or that the front brakes drag / stay on ? Is the caliper free to pivot on its mounting ? Not binding / sticking at all ? Its designed to pivot on one mounting point and slide on the other, hence the ridiculous-looking "angled" brake pads. Edited January 25, 2020 by 1600dave Quote Link to comment Share on other sites More sharing options...
Riceburner Posted January 26, 2020 Author Share Posted January 26, 2020 Hi Dave, I’ll have to check if there’s been any other mods other that the twin reservoir master. Initially it was holding pressure all the time, rock hard peddle after a few applications, brakes red hot. He opened up the master and removed this (see pic). Following that is seemed ok, now it’s started doing it again. A short drive to the local servo with half a dozen brake applications, the fronts could not be turned by hand and were red hot. After 30mins you could doing them half a turn. Front calipers have been tested and they moved freely. Quote Link to comment Share on other sites More sharing options...
1600dave Posted January 26, 2020 Share Posted January 26, 2020 I was just curious how the "plumbing" had been done - it would have originally had a single brake pipe from the master cylinder to a little brass 3-way splitter on the firewall (one to each front wheel, single line to the rear of the car). To use a dual circuit master would require completely re-doing a lot of the lines, was wondering if something was amiss there, whether the 5-way splitter / brake warning light switch had been used, etc. If its a new build, might be something as simple as wrong plumbing ? My understanding of the pressure release valve is that there are two types, one for disc and one for drum. Drum type holds more pressure and is what needs to be removed if you're doing a rear disc conversion, otherwise shouldn;t need to be touched. Is the pushrod from pedal to master correct length / correctly aligned ? I vaguely recall having to mess around with this when I fitted a 240K master to mine (replacing the single master). Quote Link to comment Share on other sites More sharing options...
Riceburner Posted January 26, 2020 Author Share Posted January 26, 2020 (edited) Attached pics and info on how he ran lines. Ok so maybe the residual pressure should go back in once the issue is fixed? He is double checking the push rod length, he did have to adjust that at install. EDIT: One thing he wasn’t certain of was how tight the front caliper nut with the split should be. Edited January 26, 2020 by Riceburner Quote Link to comment Share on other sites More sharing options...
Riceburner Posted January 26, 2020 Author Share Posted January 26, 2020 Confirmed push rod length and connection looks all ok. Quote Link to comment Share on other sites More sharing options...
1600dave Posted January 26, 2020 Share Posted January 26, 2020 (edited) I did the lines different - I used the 5-way splitter from a 180B and ditched both the original 1600 brass ones. Shouldn't make any difference though. Its been 15 years or more since I messed with original calipers, but from memory the mounting pin for the caliper on the strut is "shouldered" and you just do the castle nut up till its tight and chuck the split pin in. The spring under the nut then applies the correct pressure to allow the caliper to slide. If everything looks to be hooked up OK, only other things I can think or are whether any of the brake lines are kinked (ie pinched so fluid is slow to return), a port on the master or one of the lines has some sort of blockage, one of the pistons in the master is a bit sticky (unlikely if its new), or the pistons in the calipers are sticking. Other than that, I'm running out of ideas. One more question - is it both front wheels or just one ? Edited January 26, 2020 by 1600dave Quote Link to comment Share on other sites More sharing options...
gilltech Posted January 26, 2020 Share Posted January 26, 2020 I would start by checking the pistons in the caliphers. I had this issue with having my Zed caliphers professionally rebuilt one time, where the stock front brakes would jam on after just a few pushes on the pedal. It was obvious the pistons wouldn't return on their own for some reason and so the brakes were badly dragging. I took them back, the brake shop didn't argue just swapped in different seals - to some with a tiny fraction more clearance presumably - and all was good ever after. Quote Link to comment Share on other sites More sharing options...
Cozza Posted January 26, 2020 Share Posted January 26, 2020 Have the flexible lines been replaced? They can do funny things. Quote Link to comment Share on other sites More sharing options...
Riceburner Posted January 26, 2020 Author Share Posted January 26, 2020 (edited) Thanks for responses guys. Yeah it’s both calipers doing it. New flex lines were part of the rebuild. He did paint all of the calipers during their rebuild, I wonder if that’s binding up somewhere. Could be time to try a spare set of Calipers. Edited January 26, 2020 by Riceburner Quote Link to comment Share on other sites More sharing options...
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