You do NOT pull the cap. There is enough "slop"/gap to pull the old EPDM out and push the new epdm under the cap, using a 4 inch wide putty scraper(GENTLY). If I was doing the work on my 12 year old trailer, complete would involve what the wood substrate is like. To replace the complete epdm YOU HAVE TO INSTALL ALL NEW TOP WOOD PANELING after removing the old EPDM. For a small 4 by 8 foot area the glue will usually bond the old wood to the new EPDM. BUT trying to glue the complete roof to the old wood will result in a disaster. If once you pull the loose epdm back and you see water damage, just replace the 4 by 8 foot wood panel back to the "good" area. Replacing the complete roof on your trailer is not cost effective. At best, your model is worth no more than 20k. But, if you decide to keep it until it rots to nothing(YEARS!). it would be worth replacing the complete roof. Doug